Calling by reference

Question

I'm usually a C++ programmer, and I heard that Java and C++ were alot alike. I tried to call some variables in a function by reference, but it didn't work.
I tried calling it like:
public static void changer(int &num)
num = num * num;
I guess java doesn't like this, and I would like to know how to call my variables by reference.
Thanks.

Answer 1

Java only passes by value.Java passes primitive types (int, boolean, double,
char....) by value and most objects (not String) by
reference. Try passing an array of int's to a method
and changing it and see what happens.
// Test.java
public class Test
  public static void main(String[] args)
    int[] arr = new int[10];
    System.out.println("main: " + arr.length);
    Test.testMethod(arr, 5);
    System.out.println("main: " + arr.length);
  public static void testMethod(int[] intArray, int newSize)
    System.out.println("Test.testMethod: " + intArray.length);
    intArray = new int[newSize];
    System.out.println("Test.testMethod: " + intArray.length);
// end Test.java
C:\java>java -cp . Test
main: 10
Test.testMethod: 10
Test.testMethod: 5
main: 10Didn't pass by reference...
because Java only passes by value