Java Programs

567 Java programs, from your first Hello World to thread-safe caches. Every program comes with complete code, its exact output, a step-by-step explanation and often a second way to solve it — and you can run each one online without installing anything. Pick a topic below, or start with the programs interviewers ask most.

Most Popular Programs

Strings
Reverse a String
Control Flow
Check Prime Number
Recursion
Fibonacci Series
Recursion
Factorial
Strings
Check Palindrome String
Numbers
Check Armstrong Number
Arrays
Bubble Sort
Arrays
Find Second Largest Element in an Array
Strings
Check Anagram
Control Flow
FizzBuzz
Patterns
Print Pyramid Pattern
Collections
Count Word Frequency Using HashMap
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Java Program Topics

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Strings

53 Programs

Reverse, palindrome, anagram and more.

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Arrays

68 Programs

Array searching, sorting and more.

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Numbers

50 Programs

Prime, palindrome, Armstrong numbers and more.

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Control Flow

68 Programs

Loops, conditions and switch.

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Patterns

40 Programs

Star, number and pyramid patterns.

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Basics & I/O

55 Programs

Syntax, variables and console input.

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OOP

52 Programs

Classes, inheritance and interfaces.

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Exceptions

23 Programs

Try, catch and custom exceptions.

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Collections

68 Programs

ArrayList, HashMap and the framework.

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Recursion

25 Programs

Factorial, Fibonacci and more.

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Java 8 Streams

15 Programs

filter, map, groupingBy and collectors.

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Multithreading

20 Programs

Threads, executors and synchronization.

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File Handling

15 Programs

Read, write, copy and list files.

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Date & Time

15 Programs

Format, parse and compare dates.

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