JAVA PROGRAM • LEVEL 09 — CLASSES, OBJECTS & CONSTRUCTORS

Build Objects with Composition in Java

Learn build objects with composition in java with a complete, compiler-ready Java 17 example.

IntermediateCompositionHas-a relationship

PROBLEM UNDERSTANDING

Input and expected output

Sample input
No input required
Sample output
Asha - Hyderabad

COMPLETE JAVA 17 PROGRAM

Complete Java 17 implementation

java-object-composition.java
Open in compiler
class Address { String city; Address(String city){this.city=city;} }
class Student { String name; Address address; Student(String name,Address address){this.name=name;this.address=address;} }
class Main { public static void main(String[] args){Student student=new Student("Asha",new Address("Hyderabad"));System.out.println(student.name+" - "+student.address.city);} }

GUIDED CODE TOUR • NOT LIVE EXECUTION

Study the program line by line

Use the real compiler button above to run and debug with different inputs.

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

No line selected

EXPECTED OUTPUT FOR THE SAMPLE

Asha - Hyderabad
0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

  1. Initialize the deterministic sample values used for build objects with composition in java.
  2. Create the required object and apply Composition and Has-a relationship to its state or behavior.
  3. Print the final result and compare it with the documented sample output.

This Java 17 example demonstrates Composition and Has-a relationship 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

Time complexity

O(1)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

Check this

Keep the class name Main and the entry method signature public static void main(String[] args) when using the online compiler.

Check this

Create an object before accessing instance members; static members can be accessed through the class name.

Check this

Java is case-sensitive, and every statement that requires a semicolon must end with one.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.