Java Questions

Browse 166 questions organized into 17 categories.

Most Java questions are also available in Kotlin. (Support for Python is in alpha.)

Printing

Go Beyond Grading

Hello, world!

Variables

Practice with Primitive Types

Area Calculation

Practice with Primitive Types 2

Practice with Primitive Types 4

Practice with Variable Declaration and Initialization 0

Inspiration v. Perspiration

Conditionals

Largest of Three

Simple Conditional

Time to Decade

Print Larger, Sometimes

Center of the Universe

Print Adult Or Not

Game Tiebreaker Snippet

Quiz Score Advice

Advertising Conditional

Arrays

Array Basics

Loops

Victory Loop

Array Count Odd Snippet

Array Sum Even Snippet

Number Loop

Functions

Array Count Equal (One Dimensional)

Reverse Print

Is Even

Overloaded Multiply

Add One Function

Tic-Tac-Toe

Sum Is Odd

Is Odd

Array Range Sum

Catchup Quiz Grading

Array All Pairs

Array Is All Larger

Array Is Doubled

Accounting Calculator

Game Tiebreaker Function

Array Fill 3 Pattern

Strings

Classes

Inheritance

Course CSV to Courses

Square Shape

Simple Person Inheritance

Circle Shape

Polymorphic Greeter

Course Equality

Polymorphic Orderer

Restaurant Equality

Exceptions

Array Squares Sorted

Catching Exceptions

Insertion Sort

Insertion Sort (int)

BinarySearcher Array

BinarySearcher Array (int)

Escape a Maze

PingPonger Class

Restaurant Hash Code

Pentagon Shape

Multi Catcher

Test Array Max

Restaurant Capacity Manager

Guessing Game With Tries

Isomorphic Strings Without Map

Recursion

Mergesort

Recursive Factorial

Recursive Range Sum

Collections

Invert a Map

Count Letters with Map

Selection Sort

Unique Counter

Game CSV Sum with Map

Script Parser

Section Lists to Map

List Unique Items

Map Has Duplicate Values

Small Word Filter With List

String Duplicate Words Ignore Case

OurComparable Is Sorted

Word Lengths With Map

Cities Are Connected

Identify a Suspect

List to Set

Word Count With Map

Isomorphic Strings With Map

Last In List

Interfaces

String Length Comparable

Last Odd Interface

Both Greater Comparable

Running Total Interface

String Length Comparable Parameterized

Linked Lists

SimpleLinkedList add

SimpleLinkedList set

Binary Trees

BinaryTree Balanced

Binary Tree Search Path

Binary Tree Size

BinaryTree Values at Level (int)

BinaryTree Values at Level

Binary Tree Count Equal to Child

BinaryTree to Map

BinaryTree Count Equal Children

BinaryTree Negative Sum

Graphs

Unweighted Graph Is Undirected

Undirected Graph Size

Undirected Graph Neighborhood Count

Functional

Bracket an Anonymous Class

Adder with Lambda

String Both Ways Anonymous Class

Subtracter with Lambda