JAVA PROGRAM • LEVEL 11 — ABSTRACTION, INTERFACES & TYPE DESIGN
Use an Inner Class in Java
Learn use an inner class in java with a complete, compiler-ready Java 17 example.
PROBLEM UNDERSTANDING
Input and expected output
No input required
42
COMPLETE JAVA 17 PROGRAM
Complete Java 17 implementation
class Outer { int value=42; class Inner { int read(){return value;} } }
class Main { public static void main(String[] args){Outer outer=new Outer();System.out.println(outer.new Inner().read());} }CURRENT STEP
Select Start to walk through the important lines.
SELECTED LINE
No line selected
EXPECTED OUTPUT FOR THE SAMPLE
42
PROGRAM EXPLANATION
Algorithm and explanation
- Initialize the deterministic sample values used for use an inner class in java.
- Create the required object and apply Inner class and Outer instance to its state or behavior.
- Print the final result and compare it with the documented sample output.
This Java 17 example demonstrates Inner class and Outer instance 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(1)
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.