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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
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
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
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
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
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
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
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
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
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
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
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