JAVA PROGRAM • LEVEL 16 — LAMBDAS, STREAMS & MODERN JAVA
Use Pattern Matching with instanceof in Java
Learn use pattern matching with instanceof in java with a complete, compiler-ready Java 17 example.
PROBLEM UNDERSTANDING
Input and expected output
No input required
Integer 42 String Java
COMPLETE JAVA 17 PROGRAM
Complete Java 17 implementation
class Main{static String describe(Object value){if(value instanceof Integer number)return "Integer "+number;if(value instanceof String text)return "String "+text;return "Other";}public static void main(String[] args){System.out.println(describe(42));System.out.println(describe("Java"));}}CURRENT STEP
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SELECTED LINE
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EXPECTED OUTPUT FOR THE SAMPLE
Integer 42 String Java
PROGRAM EXPLANATION
Algorithm and explanation
- Initialize the deterministic sample values used for use pattern matching with instanceof in java.
- Apply Pattern variable and instanceof in the order shown by the program.
- Print the final result and compare it with the documented sample output.
This Java 17 example demonstrates Pattern variable and instanceof 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(n²)
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.
Use Pattern variable with compatible Java types; Java checks types and method signatures at compile time.
Java is case-sensitive, and every statement that requires a semicolon must end with one.