JAVA PROGRAM • LEVEL 15 — MULTITHREADING & CONCURRENCY
Protect a Shared Counter in Java
Learn protect a shared counter in java with a complete, compiler-ready Java 17 example.
PROBLEM UNDERSTANDING
Input and expected output
No input required
2000
COMPLETE JAVA 17 PROGRAM
Complete Java 17 implementation
class Counter{private int value; synchronized void increment(){value++;}int value(){return value;}}
class Main{public static void main(String[] args)throws Exception{Counter counter=new Counter();Thread a=new Thread(()->{for(int i=0;i<1000;i++)counter.increment();});Thread b=new Thread(()->{for(int i=0;i<1000;i++)counter.increment();});a.start();b.start();a.join();b.join();System.out.println(counter.value());}}CURRENT STEP
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SELECTED LINE
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EXPECTED OUTPUT FOR THE SAMPLE
2000
PROGRAM EXPLANATION
Algorithm and explanation
- Initialize the deterministic sample values used for protect a shared counter in java.
- Create the required object and apply synchronized and Race condition to its state or behavior.
- Print the final result and compare it with the documented sample output.
This Java 17 example demonstrates synchronized and Race condition through a complete, executable program. The values are intentionally small so students can trace each statement, verify the output, and then modify the example safely in the online compiler.
EFFICIENCY
Time and space complexity
O(n)
O(1)
DEBUGGING CHECKLIST
Common mistakes
Keep the class name Main and the entry method signature public static void main(String[] args) when using the online compiler.
Create an object before accessing instance members; static members can be accessed through the class name.
Java is case-sensitive, and every statement that requires a semicolon must end with one.