Learn CS Online: Java Practice

Kotlin

Java

294 Java questions for you to practice.

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Hello, world!

Hello, learncs.online!

System.out.println

Hello, world!

System.out.println

Variables and Types

Practice with Primitive Types

initializing variables

declaring variables

Practice with Primitive Types 2

initializing variables

declaring variables

Practice with Variable Declaration and Initialization 0

initializing variables

declaring variables

Operations on Variables

Area Calculation

arithmetic

initializing variables

declaring variables

Inspiration v. Perspiration

arithmetic

initializing variables

declaring variables

Conditional Expressions and Statements

Advertising Conditional

if-else statements

if statements

comparisons

System.out.println

Simple Conditional

if-else statements

if statements

comparisons

System.out.println

Largest of Three

if statements

comparisons

modifying variables

initializing variables

declaring variables

System.out.println

Print Larger, Sometimes

nested conditionals

if-else statements

if statements

comparisons

System.out.println

Compound Conditionals

Print Adult Or Not

logical operators

nested conditionals

if-else statements

if statements

comparisons

System.out.println

Quiz Score Advice

if-else-if statements

if-else statements

if statements

comparisons

System.out.println

Game Tiebreaker Snippet

if-else-if statements

nested conditionals

if-else statements

if statements

comparisons

modifying variables

Arrays

Array Basics

accessing arrays

using arrays

modifying variables

initializing variables

declaring variables

System.out.println

Loops

Number Loop

for loops

comparisons

variable operations

modifying variables

initializing variables

declaring variables

System.out.println

Victory Loop

for loops

comparisons

variable operations

modifying variables

initializing variables

declaring variables

System.out.println

Array Count Odd Snippet

for loops

accessing arrays

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

System.out.println

Array Sum Even Snippet

for loops

accessing arrays

reference equality

if statements

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

System.out.println

Functions

Add One Function

return

declaring methods

arithmetic

Is Odd

return

declaring methods

reference equality

comparisons

arithmetic

Make Ends

return

declaring methods

accessing arrays

arithmetic

Make Middle

return

declaring methods

accessing arrays

arithmetic

Make Pi

return

declaring methods

Mid Three

return

declaring methods

accessing arrays

arithmetic

Middle Way

return

declaring methods

accessing arrays

Reverse Three

return

declaring methods

accessing arrays

Rotate Left 3

return

declaring methods

accessing arrays

Sum 3

return

declaring methods

accessing arrays

arithmetic

Sum Is Odd

return

declaring methods

reference equality

comparisons

arithmetic

Swap Ends

return

declaring methods

accessing arrays

arithmetic

modifying variables

initializing variables

declaring variables

Two Last Digit

return

declaring methods

reference equality

comparisons

arithmetic

Accounting Calculator

return

declaring methods

for loops

accessing arrays

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Bigger Two

return

declaring methods

accessing arrays

if-else statements

if statements

comparisons

arithmetic

initializing variables

declaring variables

Common End

return

declaring methods

accessing arrays

logical operators

reference equality

comparisons

arithmetic

Less 20

return

declaring methods

logical operators

reference equality

comparisons

arithmetic

Max End 3

return

declaring methods

accessing arrays

if statements

comparisons

modifying variables

initializing variables

declaring variables

More 20

return

declaring methods

logical operators

reference equality

comparisons

arithmetic

Near 10

return

declaring methods

logical operators

comparisons

arithmetic

Or 35

return

declaring methods

logical operators

reference equality

comparisons

arithmetic

Overloaded Multiply

return

declaring methods

arithmetic

Reverse Print

return

declaring methods

for loops

accessing arrays

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

System.out.println

Same First Last

return

declaring methods

accessing arrays

logical operators

reference equality

comparisons

arithmetic

Sleep In

return

declaring methods

logical operators

Special Eleven

return

declaring methods

logical operators

reference equality

comparisons

arithmetic

Sum Double

return

declaring methods

reference equality

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

firstLast6

return

declaring methods

accessing arrays

logical operators

reference equality

comparisons

arithmetic

Array Count Equal (One Dimensional)

return

declaring methods

for loops

accessing arrays

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Catchup Quiz Grading

return

declaring methods

for loops

accessing arrays

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Cigar Party

return

declaring methods

logical operators

if-else statements

if statements

comparisons

Front Piece

return

declaring methods

accessing arrays

if-else-if statements

reference equality

if-else statements

if statements

comparisons

In Order

return

declaring methods

logical operators

if-else statements

if statements

comparisons

Make 2

return

declaring methods

accessing arrays

using arrays

if-else-if statements

reference equality

if-else statements

if statements

comparisons

modifying variables

initializing variables

declaring variables

Make Chocolate

return

declaring methods

if-else statements

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

Makes 10

return

declaring methods

logical operators

reference equality

comparisons

arithmetic

Max Triple

return

declaring methods

accessing arrays

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

Old 35

return

declaring methods

logical operators

reference equality

comparisons

arithmetic

Parrot Trouble

return

declaring methods

logical operators

comparisons

Sorta Sum

return

declaring methods

logical operators

if-else statements

if statements

comparisons

arithmetic

initializing variables

declaring variables

Sum 2

return

declaring methods

accessing arrays

if statements

comparisons

variables assignment

modifying variables

initializing variables

declaring variables

Three Last Digit

return

declaring methods

logical operators

reference equality

comparisons

arithmetic

Two As One

return

declaring methods

logical operators

reference equality

comparisons

arithmetic

int Max

return

declaring methods

if-else statements

if statements

comparisons

modifying variables

declaring variables

Answer Cell

return

declaring methods

if-else-if statements

logical operators

if-else statements

if statements

Array Front 9

return

declaring methods

for loops

accessing arrays

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Array Is Doubled

return

declaring methods

for loops

accessing arrays

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Caught Speeding

return

declaring methods

if-else-if statements

if-else statements

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

Game Tiebreaker Function

return

declaring methods

if-else-if statements

nested conditionals

if-else statements

if statements

comparisons

Has 23

return

declaring methods

accessing arrays

logical operators

reference equality

comparisons

Icy Hot

return

declaring methods

logical operators

comparisons

In 1 to 10

return

declaring methods

logical operators

if-else statements

if statements

comparisons

In 10..20

return

declaring methods

logical operators

comparisons

In Order Equals

return

declaring methods

logical operators

if-else statements

if statements

comparisons

Lucky Sum

return

declaring methods

if-else-if statements

reference equality

if-else statements

if statements

comparisons

arithmetic

Make Bricks

return

declaring methods

logical operators

comparisons

arithmetic

Monkey Trouble

return

declaring methods

logical operators

if statements

No 23

return

declaring methods

accessing arrays

logical operators

reference equality

comparisons

No Triples

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Share Digit

return

declaring methods

if-else-if statements

reference equality

if-else statements

if statements

comparisons

arithmetic

Squirrel Play

return

declaring methods

logical operators

if-else statements

if statements

comparisons

Without Doubles

return

declaring methods

logical operators

reference equality

nested conditionals

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

Array 123

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Array 667

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

nested conditionals

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Array All Pairs

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if statements

comparisons

variables assignment

arithmetic

modifying variables

initializing variables

declaring variables

Date Fashion

return

declaring methods

if-else-if statements

logical operators

if-else statements

if statements

comparisons

Double 23

return

declaring methods

accessing arrays

logical operators

reference equality

if statements

comparisons

Fix 23

return

declaring methods

accessing arrays

logical operators

reference equality

if statements

comparisons

modifying variables

Front 11

return

declaring methods

accessing arrays

if-else-if statements

logical operators

reference equality

if-else statements

if statements

comparisons

Max Mod 5

return

declaring methods

if-else-if statements

reference equality

nested conditionals

if-else statements

if statements

comparisons

arithmetic

Start 1

return

declaring methods

accessing arrays

logical operators

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Tea Party

return

declaring methods

if-else-if statements

logical operators

if-else statements

if statements

comparisons

arithmetic

Teen Sum

return

declaring methods

logical operators

if-else statements

if statements

comparisons

arithmetic

Array Is All Larger

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Blackjack

return

declaring methods

if-else-if statements

logical operators

if-else statements

if statements

comparisons

arithmetic

Blue Ticket

return

declaring methods

if-else-if statements

logical operators

reference equality

if-else statements

if statements

comparisons

arithmetic

Green Ticket

return

declaring methods

if-else-if statements

logical operators

reference equality

if-else statements

if statements

comparisons

Has Teen

return

declaring methods

logical operators

comparisons

Lone Teen

return

declaring methods

logical operators

comparisons

initializing variables

declaring variables

Max 10..20

return

declaring methods

logical operators

if statements

comparisons

modifying variables

initializing variables

declaring variables

Pos Neg

return

declaring methods

logical operators

if-else statements

if statements

comparisons

Lone Sum

return

declaring methods

logical operators

reference equality

if statements

comparisons

variables assignment

arithmetic

modifying variables

initializing variables

declaring variables

In 30..50

return

declaring methods

logical operators

if statements

comparisons

Red Ticket

return

declaring methods

if-else-if statements

logical operators

reference equality

if-else statements

if statements

comparisons

Tic-Tac-Toe

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Unlucky 1

return

declaring methods

accessing arrays

logical operators

reference equality

comparisons

arithmetic

Practice with Functions

Array Count 9

enhanced for loop

return

declaring methods

for loops

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Array Range Sum

enhanced for loop

return

declaring methods

for loops

logical operators

if statements

comparisons

variables assignment

arithmetic

modifying variables

initializing variables

declaring variables

Strings

Back Around

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

initializing variables

declaring variables

Email to NetID

dotted method calls

dot notation

Strings

assert statements

return

declaring methods

accessing arrays

using arrays

initializing variables

declaring variables

equality

Endsly

dotted method calls

dot notation

Strings

return

declaring methods

First Half

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

Hello Name

Strings

return

declaring methods

arithmetic

Make ABBA

Strings

return

declaring methods

arithmetic

Make Out Word

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

Make Tags

Strings

return

declaring methods

arithmetic

Middle Three

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

Middle Two

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

Missing Char

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

initializing variables

declaring variables

Mix Start

dotted method calls

dot notation

Strings

return

declaring methods

Non Start

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

Reformat a Phone Number

dotted method calls

dot notation

Strings

return

declaring methods

accessing arrays

using arrays

arithmetic

initializing variables

declaring variables

Right 2

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

Rotate Left 2

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

Start Hi

dotted method calls

dot notation

Strings

return

declaring methods

Without End

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

nTwice

dotted method calls

dot notation

Strings

return

declaring methods

arithmetic

Combo String

dotted method calls

dot notation

Strings

return

declaring methods

if-else statements

if statements

comparisons

arithmetic

Diff 21

dotted method calls

dot notation

return

declaring methods

if-else statements

if statements

comparisons

arithmetic

Double Char

dotted method calls

dot notation

Strings

enhanced for loop

return

declaring methods

for loops

variables assignment

arithmetic

modifying variables

initializing variables

declaring variables

Ends Up

dotted method calls

dot notation

Strings

return

declaring methods

if statements

comparisons

arithmetic

initializing variables

declaring variables

Every Nth

dotted method calls

dot notation

Strings

return

declaring methods

for loops

comparisons

variables assignment

modifying variables

initializing variables

declaring variables

Extra Front

dotted method calls

dot notation

Strings

return

declaring methods

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

First Two

dotted method calls

dot notation

Strings

return

declaring methods

if statements

comparisons

Front 22

dotted method calls

dot notation

Strings

return

declaring methods

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

Front 3

dotted method calls

dot notation

Strings

return

declaring methods

if-else statements

if statements

comparisons

arithmetic

modifying variables

declaring variables

Front Again

dotted method calls

dot notation

Strings

return

declaring methods

if statements

comparisons

arithmetic

equality

Last Two

dotted method calls

dot notation

Strings

return

declaring methods

if-else statements

if statements

comparisons

arithmetic

Last Value From String

dotted method calls

dot notation

Strings

enhanced for loop

return

declaring methods

for loops

modifying variables

initializing variables

declaring variables

Near Hundred

dotted method calls

dot notation

return

declaring methods

logical operators

comparisons

arithmetic

Repeat End

dotted method calls

dot notation

Strings

return

declaring methods

for loops

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Repeat Front

dotted method calls

dot notation

Strings

return

declaring methods

for loops

comparisons

variables assignment

variable operations

modifying variables

initializing variables

declaring variables

String Bits

dotted method calls

dot notation

Strings

return

declaring methods

for loops

comparisons

variables assignment

arithmetic

modifying variables

initializing variables

declaring variables

String Flip Halves

dotted method calls

dot notation

Strings

return

declaring methods

reference equality

if-else statements

if statements

comparisons

arithmetic

initializing variables

declaring variables

String Reverse

dotted method calls

dot notation

Strings

return

declaring methods

for loops

accessing arrays

using arrays

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

String Splotion

dotted method calls

dot notation

Strings

return

declaring methods

for loops

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

String Times

Strings

return

declaring methods

for loops

comparisons

variables assignment

variable operations

modifying variables

initializing variables

declaring variables

Sum Limit

dotted method calls

dot notation

return

declaring methods

if-else statements

if statements

comparisons

arithmetic

initializing variables

declaring variables

The End

dotted method calls

dot notation

Strings

return

declaring methods

if-else statements

if statements

arithmetic

Without End 2

dotted method calls

dot notation

Strings

return

declaring methods

if-else statements

if statements

comparisons

arithmetic

delDel

dotted method calls

dot notation

Strings

return

declaring methods

if statements

arithmetic

notString

dotted method calls

dot notation

Strings

return

declaring methods

if statements

arithmetic

oneTwo

dotted method calls

dot notation

Strings

return

declaring methods

for loops

comparisons

variables assignment

arithmetic

modifying variables

initializing variables

declaring variables

At First

dotted method calls

dot notation

Strings

return

declaring methods

if-else-if statements

reference equality

if-else statements

if statements

comparisons

arithmetic

Close 10

dotted method calls

dot notation

return

declaring methods

if-else-if statements

if-else statements

if statements

comparisons

arithmetic

initializing variables

declaring variables

Count Hi

dotted method calls

dot notation

Strings

return

declaring methods

for loops

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

equality

Count XX

dotted method calls

dot notation

Strings

return

declaring methods

for loops

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Double X

dotted method calls

dot notation

Strings

return

declaring methods

reference equality

if statements

comparisons

arithmetic

initializing variables

declaring variables

End Other

dotted method calls

dot notation

Strings

return

declaring methods

if-else-if statements

reference equality

if-else statements

if statements

comparisons

arithmetic

equality

Front Times

dotted method calls

dot notation

Strings

return

declaring methods

for loops

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Has Bad

dotted method calls

dot notation

Strings

return

declaring methods

logical operators

comparisons

Last Chars

dotted method calls

dot notation

Strings

return

declaring methods

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

Less By 10

dotted method calls

dot notation

return

declaring methods

logical operators

comparisons

arithmetic

Min Cat

dotted method calls

dot notation

Strings

return

declaring methods

if-else-if statements

reference equality

if-else statements

if statements

comparisons

arithmetic

Prefix Again

dotted method calls

dot notation

Strings

return

declaring methods

for loops

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

equality

Reformat Name and Age Records

dotted method calls

dot notation

Strings

enhanced for loop

return

declaring methods

for loops

accessing arrays

using arrays

reference equality

if-else statements

if statements

comparisons

variables assignment

arithmetic

modifying variables

initializing variables

declaring variables

See Color

dotted method calls

dot notation

Strings

return

declaring methods

if-else-if statements

if-else statements

if statements

Start Word

dotted method calls

dot notation

Strings

return

declaring methods

logical operators

if-else statements

if statements

comparisons

String Match

dotted method calls

dot notation

Strings

return

declaring methods

for loops

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

equality

Two Char

dotted method calls

dot notation

Strings

return

declaring methods

logical operators

if-else statements

if statements

comparisons

arithmetic

Without 2

dotted method calls

dot notation

Strings

return

declaring methods

if-else statements

if statements

comparisons

arithmetic

equality

Without X

dotted method calls

dot notation

Strings

return

declaring methods

if statements

arithmetic

modifying variables

initializing variables

declaring variables

altPairs

dotted method calls

dot notation

Strings

return

declaring methods

for loops

if statements

comparisons

variables assignment

arithmetic

modifying variables

initializing variables

declaring variables

Bob There

dotted method calls

dot notation

Strings

return

declaring methods

for loops

accessing arrays

using arrays

logical operators

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Cat Dog

dotted method calls

dot notation

Strings

return

declaring methods

for loops

if-else-if statements

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

equality

Has 271

dotted method calls

dot notation

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Last2

dotted method calls

dot notation

Strings

return

declaring methods

for loops

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

equality

Love 8

dotted method calls

dot notation

return

declaring methods

logical operators

reference equality

comparisons

arithmetic

Mario Bricks

Strings

nested loops

return

declaring methods

for loops

if-else statements

if statements

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Same Star Character

dotted method calls

dot notation

Strings

return

declaring methods

continue

for loops

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

conCat

dotted method calls

dot notation

Strings

return

declaring methods

if-else-if statements

reference equality

if-else statements

if statements

comparisons

arithmetic

plus Out

dotted method calls

dot notation

Strings

return

declaring methods

for loops

logical operators

if-else statements

if statements

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

equality

stringE

dotted method calls

dot notation

Strings

enhanced for loop

return

declaring methods

for loops

logical operators

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

xy Balance

dotted method calls

dot notation

Strings

return

declaring methods

continue

for loops

logical operators

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

xyz Middle

dotted method calls

dot notation

Strings

return

declaring methods

logical operators

reference equality

if statements

comparisons

arithmetic

initializing variables

declaring variables

equality

Count Code

dotted method calls

dot notation

Strings

return

declaring methods

for loops

accessing arrays

using arrays

logical operators

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Fizz String

dotted method calls

dot notation

Strings

return

declaring methods

if-else-if statements

logical operators

reference equality

if-else statements

if statements

comparisons

arithmetic

Fizz String 2

Strings

return

declaring methods

if-else-if statements

logical operators

reference equality

if-else statements

if statements

comparisons

arithmetic

Mix String

dotted method calls

dot notation

Strings

return

declaring methods

for loops

if-else-if statements

logical operators

if statements

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Small Word Filter With Array

dotted method calls

dot notation

Strings

enhanced for loop

return

declaring methods

for loops

accessing arrays

using arrays

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Start Oz

dotted method calls

dot notation

Strings

return

declaring methods

logical operators

reference equality

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

String X

dotted method calls

dot notation

Strings

return

declaring methods

for loops

logical operators

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

String Yak

dotted method calls

dot notation

Strings

return

declaring methods

for loops

logical operators

reference equality

if-else statements

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

xyz There

dotted method calls

dot notation

Strings

return

declaring methods

for loops

logical operators

reference equality

nested conditionals

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

equality

Alarm Clock

Strings

return

declaring methods

logical operators

reference equality

nested conditionals

if-else statements

if statements

comparisons

Close Far

dotted method calls

dot notation

return

declaring methods

logical operators

comparisons

arithmetic

Without X2

dotted method calls

dot notation

Strings

return

declaring methods

logical operators

reference equality

if statements

comparisons

variables assignment

modifying variables

initializing variables

declaring variables

deFront

dotted method calls

dot notation

Strings

return

declaring methods

logical operators

reference equality

if statements

comparisons

variables assignment

modifying variables

initializing variables

declaring variables

Star Out

dotted method calls

dot notation

Strings

return

declaring methods

continue

for loops

if-else-if statements

logical operators

reference equality

if statements

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Evenly Spaced

dotted method calls

dot notation

return

declaring methods

logical operators

reference equality

if statements

comparisons

arithmetic

initializing variables

declaring variables

Algorithms and Strings

Print Number Summary

primitive type casting

dotted method calls

dot notation

Strings

enhanced for loop

declaring methods

continue

for loops

reference equality

if-else statements

if statements

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

System.out.println

null

Array Count Greater Than 1D

working with null

assert statements

return

declaring methods

for loops

accessing arrays

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Array Sum (Two Dimensional)

working with null

nested loops

return

declaring methods

for loops

accessing arrays

reference equality

if statements

comparisons

variables assignment

variable operations

modifying variables

initializing variables

declaring variables

Rot 13 Encryption

working with null

dotted method calls

dot notation

Strings

return

declaring methods

for loops

accessing arrays

using arrays

reference equality

if statements

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

2D Array Max Subarray Sum

working with null

nested loops

assert statements

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if statements

comparisons

variables assignment

variable operations

modifying variables

initializing variables

declaring variables

Array Max (1D)

working with null

return

declaring methods

for loops

accessing arrays

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

String Rotate Right

working with null

dotted method calls

dot notation

Strings

return

declaring methods

for loops

accessing arrays

using arrays

logical operators

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Multidimensional Arrays

Array Fill 3 Pattern

using multi-dimensional arrays

nested loops

return

declaring methods

for loops

accessing arrays

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Lists and Type Parameters

Last In List

type parameters

dotted method calls

dot notation

return

declaring methods

arithmetic

Small Word Filter With List

type parameters

dotted method calls

dot notation

creating objects

Strings

enhanced for loop

return

declaring methods

for loops

using arrays

if statements

comparisons

initializing variables

declaring variables

Maps and Sets

Identify a Suspect

type parameters

dotted method calls

dot notation

creating objects

Strings

return

declaring methods

initializing variables

declaring variables

List to Set

type parameters

working with null

dotted method calls

dot notation

creating objects

Strings

enhanced for loop

assert statements

return

declaring methods

for loops

reference equality

comparisons

initializing variables

declaring variables

Word Count With Map

type parameters

boxing classes

dotted method calls

dot notation

creating objects

Strings

enhanced for loop

return

declaring methods

for loops

using arrays

arithmetic

initializing variables

declaring variables

Word Lengths With Map

type parameters

boxing classes

working with null

dotted method calls

dot notation

creating objects

Strings

enhanced for loop

assert statements

return

declaring methods

for loops

using arrays

reference equality

comparisons

initializing variables

declaring variables

Map Has Duplicate Values

type parameters

dotted method calls

dot notation

creating objects

Strings

enhanced for loop

return

declaring methods

for loops

if statements

initializing variables

declaring variables

Script Parser

type parameters

working with null

dotted method calls

dot notation

creating objects

Strings

enhanced for loop

assert statements

return

declaring methods

for loops

accessing arrays

using arrays

logical operators

reference equality

if statements

comparisons

initializing variables

declaring variables

Section Lists to Map

type parameters

working with null

dotted method calls

dot notation

creating objects

Strings

enhanced for loop

nested loops

assert statements

return

declaring methods

for loops

accessing arrays

using arrays

reference equality

comparisons

variable operations

modifying variables

initializing variables

declaring variables

String Duplicate Words Ignore Case

type parameters

working with null

dotted method calls

dot notation

creating objects

Strings

enhanced for loop

assert statements

return

declaring methods

for loops

using arrays

reference equality

if statements

comparisons

initializing variables

declaring variables

Encapsulation

Counter Object

public and private

class field

declaring classes

return

declaring methods

variable operations

modifying variables

Format Date Method

public and private

declaring classes

import statements

dotted method calls

dot notation

Strings

return

declaring methods

Make Last

public and private

return

declaring methods

accessing arrays

using arrays

arithmetic

modifying variables

initializing variables

declaring variables

Object with Public Value

writing getters

working with null

dotted variable accesses

dot notation

assert statements

return

declaring methods

reference equality

comparisons

Plus Two

public and private

return

declaring methods

accessing arrays

Course Hash Code

final fields

public and private

constructors

class field

declaring classes

import statements

dotted method calls

dot notation

Strings

return

declaring methods

modifying variables

Flop Flip Object

public and private

constructors

class field

declaring classes

return

declaring methods

logical operators

modifying variables

Last 8

final fields

public and private

class field

declaring classes

return

declaring methods

accessing arrays

arithmetic

modifying variables

Simple Object Field

public and private

writing setters

writing getters

class field

declaring classes

return

declaring methods

modifying variables

Simple Object Field 2

public and private

writing setters

writing getters

class field

declaring classes

Strings

return

declaring methods

modifying variables

Simple Object Method

public and private

writing setters

class field

declaring classes

return

declaring methods

arithmetic

modifying variables

Simple Object Method 2

public and private

writing setters

class field

declaring classes

return

declaring methods

arithmetic

modifying variables

Toggler Object

public and private

constructors

class field

declaring classes

return

declaring methods

logical operators

modifying variables

Compare Date Strings

public and private

declaring classes

import statements

dotted method calls

dot notation

Strings

return

declaring methods

if-else-if statements

if-else statements

if statements

comparisons

initializing variables

declaring variables

Guessing Game

writing getters

working with null

dotted method calls

dot notation

assert statements

return

declaring methods

for loops

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Round Sum

public and private

return

declaring methods

if-else statements

if statements

comparisons

arithmetic

initializing variables

declaring variables

Course Getters and Setters

final fields

public and private

writing setters

writing getters

constructors

class field

declaring classes

working with null

Strings

assert statements

return

declaring methods

reference equality

comparisons

modifying variables

Last 4 In Order

final fields

public and private

class field

declaring classes

return

declaring methods

for loops

accessing arrays

if-else statements

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Restaurant Getters and Setters

final fields

public and private

writing setters

writing getters

constructors

class field

declaring classes

working with null

Strings

assert statements

return

declaring methods

reference equality

comparisons

modifying variables

Score Tracker

public and private

class field

declaring classes

return

declaring methods

if-else-if statements

logical operators

if-else statements

if statements

comparisons

variables assignment

modifying variables

SimpleArrayList get and set

final fields

public and private

writing setters

writing getters

constructors

class field

declaring classes

working with null

assert statements

return

declaring methods

accessing arrays

logical operators

reference equality

comparisons

modifying variables

No Teen Sum

public and private

return

declaring methods

logical operators

reference equality

if-else statements

if statements

comparisons

arithmetic

Count DNA Subsequence

public and private

working with null

dotted method calls

dot notation

Strings

return

declaring methods

for loops

logical operators

reference equality

if statements

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

equality

SimpleArrayList add

public and private

writing getters

constructors

class field

declaring classes

working with null

assert statements

return

declaring methods

for loops

accessing arrays

using arrays

logical operators

reference equality

if-else statements

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Static

Static Adder

static methods

public and private

declaring classes

return

declaring methods

arithmetic

Test Array Sum

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

assert statements

declaring methods

reference equality

comparisons

Mystery Method 1

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

Strings

assert statements

return

declaring methods

reference equality

if-else statements

if statements

comparisons

arithmetic

Mystery Method 2

static methods

public and private

declaring classes

dotted method calls

dot notation

enhanced for loop

return

declaring methods

for loops

using arrays

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Object Array Shallow Copy

static methods

public and private

declaring classes

working with null

return

declaring methods

for loops

accessing arrays

using arrays

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Object v. Reference Equality

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

return

declaring methods

if-else-if statements

reference equality

if-else statements

if statements

comparisons

equality

OurComparable Max

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

assert statements

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Quicksort Partition (First Value)

static methods

public and private

declaring classes

working with null

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

Return an Exception

static methods

public and private

declaring classes

creating objects

assert statements

return

declaring methods

if-else-if statements

logical operators

reference equality

if-else statements

if statements

comparisons

List Unique Items

static methods

public and private

declaring classes

type parameters

import statements

dotted method calls

dot notation

nested loops

return

declaring methods

continue

break

for loops

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

equality

Inheritance

Simple Person Inheritance

calling super

extending classes

final fields

public and private

writing getters

constructors

class field

declaring classes

Strings

assert statements

return

declaring methods

comparisons

modifying variables

Polymorphism

Polymorphic Greeter

instanceof type checking

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

Strings

return

declaring methods

if-else-if statements

if statements

arithmetic

Polymorphic Orderer

instanceof type checking

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

Strings

return

declaring methods

if-else-if statements

if statements

arithmetic

Restaurant Equality

instanceof type checking

final fields

public and private

constructors

class field

declaring classes

working with null

dotted variable accesses

dotted method calls

dot notation

Strings

assert statements

return

declaring methods

logical operators

reference equality

if statements

comparisons

modifying variables

equality

Course Equality

instanceof type checking

this keyword

final fields

public and private

constructors

class field

declaring classes

working with null

dotted variable accesses

dotted method calls

dot notation

Strings

assert statements

return

declaring methods

logical operators

reference equality

if statements

comparisons

modifying variables

equality

Catching Exceptions

Multi Catcher

try-catch

static methods

public and private

declaring classes

dotted method calls

dot notation

return

declaring methods

while loops

Test Array Max

try-catch

instanceof type checking

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

assert statements

declaring methods

reference equality

comparisons

Catching Exceptions

try-catch

static methods

public and private

declaring classes

dotted method calls

dot notation

return

declaring methods

Throwing Exceptions

Escape a Maze

throwing exceptions

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

creating objects

nested loops

return

declaring methods

while loops

logical operators

reference equality

if statements

comparisons

OurComparable Is Sorted

throwing exceptions

static methods

public and private

declaring classes

type parameters

import statements

working with null

dotted method calls

dot notation

creating objects

return

declaring methods

for loops

logical operators

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Pentagon Shape

throwing exceptions

instanceof type checking

calling super

extending classes

final fields

public and private

constructors

class field

declaring classes

dotted variable accesses

dotted method calls

dot notation

creating objects

return

declaring methods

logical operators

reference equality

if statements

comparisons

arithmetic

modifying variables

Restaurant Hash Code

throwing exceptions

final fields

public and private

constructors

class field

declaring classes

import statements

working with null

dotted method calls

dot notation

creating objects

Strings

return

declaring methods

logical operators

reference equality

if statements

comparisons

modifying variables

Guessing Game With Tries

throwing exceptions

final fields

public and private

writing getters

constructors

class field

declaring classes

creating objects

return

declaring methods

logical operators

reference equality

if-else statements

if statements

comparisons

variable operations

modifying variables

Isomorphic Strings With Map

throwing exceptions

static methods

public and private

declaring classes

type parameters

boxing classes

import statements

working with null

dotted method calls

dot notation

creating objects

Strings

return

declaring methods

for loops

logical operators

reference equality

nested conditionals

if-else statements

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

equality

Cities Are Connected

throwing exceptions

final fields

public and private

constructors

class field

declaring classes

type parameters

import statements

working with null

dotted method calls

dot notation

creating objects

Strings

enhanced for loop

nested loops

return

declaring methods

for loops

accessing arrays

using arrays

reference equality

if statements

comparisons

variable operations

modifying variables

initializing variables

declaring variables

PingPonger Class

throwing exceptions

public and private

constructors

class field

declaring classes

dotted method calls

dot notation

creating objects

Strings

return

declaring methods

if-else-if statements

logical operators

if-else statements

if statements

modifying variables

equality

Isomorphic Strings Without Map

throwing exceptions

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

creating objects

Strings

nested loops

return

declaring methods

continue

for loops

accessing arrays

using arrays

logical operators

reference equality

nested conditionals

if-else statements

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Restaurant Capacity Manager

checked exceptions

throwing exceptions

final fields

public and private

constructors

class field

declaring classes

creating objects

return

declaring methods

if statements

comparisons

variables assignment

arithmetic

modifying variables

Using Interfaces

Insertion Sort

using the Comparable interface

throwing exceptions

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

creating objects

nested loops

return

declaring methods

break

for loops

accessing arrays

reference equality

if-else statements

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

BinarySearcher Array

using the Comparable interface

throwing exceptions

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

creating objects

return

declaring methods

while loops

if-else-if statements

logical operators

reference equality

if-else statements

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

Implementing Interfaces

Last Odd Interface

implementing interfaces

public and private

class field

declaring classes

return

declaring methods

reference equality

comparisons

arithmetic

modifying variables

Running Total Interface

implementing interfaces

public and private

class field

declaring classes

return

declaring methods

variables assignment

modifying variables

String Length Comparable Parameterized

implementing interfaces

using the Comparable interface

final fields

public and private

constructors

class field

declaring classes

type parameters

working with null

dotted variable accesses

dotted method calls

dot notation

Strings

assert statements

return

declaring methods

if-else-if statements

reference equality

if-else statements

if statements

comparisons

modifying variables

Both Greater Comparable

implementing interfaces

using the Comparable interface

final fields

public and private

constructors

class field

declaring classes

type parameters

dotted variable accesses

dot notation

return

declaring methods

if-else-if statements

logical operators

if-else statements

if statements

comparisons

modifying variables

Anonymous Classes

Bracket an Anonymous Class

anonymous classes

static methods

public and private

declaring classes

creating objects

return

declaring methods

String Both Ways Anonymous Class

anonymous classes

throwing exceptions

static methods

public and private

declaring classes

working with null

dotted method calls

dot notation

creating objects

Strings

return

declaring methods

for loops

accessing arrays

using arrays

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Lambda Expressions

Adder with Lambda

lambda expressions

static methods

public and private

declaring classes

return

declaring methods

arithmetic

Subtracter with Lambda

lambda expressions

static methods

public and private

declaring classes

return

declaring methods

arithmetic

Linked Lists

SimpleLinkedList set

inner classes

public and private

writing setters

writing getters

constructors

class field

declaring classes

working with null

dotted variable accesses

dot notation

creating objects

assert statements

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

SimpleLinkedList add

inner classes

public and private

writing setters

writing getters

constructors

class field

declaring classes

working with null

dotted variable accesses

dot notation

creating objects

assert statements

return

declaring methods

for loops

accessing arrays

logical operators

reference equality

if-else statements

if statements

comparisons

variables assignment

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Recursion

Mergesort

throwing exceptions

extending classes

public and private

declaring classes

working with null

creating objects

return

declaring methods

reference equality

if statements

comparisons

arithmetic

Recursive Factorial

throwing exceptions

static methods

public and private

declaring classes

creating objects

return

declaring methods

logical operators

reference equality

if statements

comparisons

arithmetic

Recursive Range Sum

throwing exceptions

static methods

public and private

declaring classes

creating objects

return

declaring methods

logical operators

reference equality

if statements

comparisons

arithmetic

Trees and Recursion

Binary Tree Size

static methods

public and private

declaring classes

type parameters

import statements

working with null

dotted method calls

dot notation

return

declaring methods

reference equality

if statements

comparisons

arithmetic

BinaryTree Negative Sum

static methods

public and private

declaring classes

type parameters

boxing classes

import statements

working with null

dotted method calls

dot notation

return

declaring methods

reference equality

if-else statements

if statements

comparisons

arithmetic

BinaryTree Count Equal Children

static methods

public and private

declaring classes

type parameters

import statements

working with null

dotted method calls

dot notation

return

declaring methods

logical operators

reference equality

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

equality

BinaryTree to Map

throwing exceptions

static methods

public and private

declaring classes

type parameters

boxing classes

import statements

working with null

dotted method calls

dot notation

creating objects

return

declaring methods

reference equality

if statements

comparisons

arithmetic

initializing variables

declaring variables

Binary Tree Count Equal to Child

static methods

public and private

declaring classes

import statements

working with null

dotted method calls

dot notation

return

declaring methods

logical operators

reference equality

if statements

comparisons

arithmetic

modifying variables

initializing variables

declaring variables

equality

BinaryTree Balanced

throwing exceptions

static methods

public and private

declaring classes

import statements

working with null

dotted method calls

dot notation

creating objects

return

declaring methods

logical operators

reference equality

if statements

comparisons

arithmetic

initializing variables

declaring variables

Binary Tree Search Path

throwing exceptions

static methods

public and private

declaring classes

type parameters

import statements

working with null

dotted method calls

dot notation

creating objects

return

declaring methods

logical operators

reference equality

if-else statements

if statements

comparisons

initializing variables

declaring variables

equality

Graphs

Undirected Graph Size

throwing exceptions

static methods

public and private

declaring classes

type parameters

boxing classes

import statements

working with null

dotted method calls

dot notation

creating objects

enhanced for loop

return

declaring methods

for loops

logical operators

reference equality

if statements

comparisons

initializing variables

declaring variables

Unweighted Graph Is Undirected

throwing exceptions

static methods

public and private

declaring classes

type parameters

import statements

working with null

dotted method calls

dot notation

creating objects

enhanced for loop

nested loops

return

declaring methods

for loops

logical operators

reference equality

if statements

comparisons

declaring variables

Undirected Graph Neighborhood Count

throwing exceptions

static methods

public and private

declaring classes

type parameters

boxing classes

import statements

working with null

dotted method calls

dot notation

creating objects

enhanced for loop

return

declaring methods

for loops

logical operators

reference equality

if statements

comparisons

arithmetic

variable operations

modifying variables

initializing variables

declaring variables

Java

Kotlin