Java uses the pass-by value.
Java copies and passes object reference by value too, not the object. With a copy of the object reference, a Java method can manipulate the mutable fields of the object (see example 1 below), but a Java method can NOT change the original reference (see example 2 below).
Example 1:
public void mutate(MyObject arg1) {
arg1.field1 = new_value;
}
The code above will change the field 1 of MyObject.
Example 2:
public void swap(MyObject arg1, MyObject arg2) {
arg1 = arg2;
}
public void callee() {
myObj1.field1 = value_1;
myObj2.field1 = not_value_1;
swap(myObj1, myObj2);
// myObj1.field1 would still hold the value of “value_1″.
}
A good reference document can be found in one of the JavaWorld article published in the year of 2000. “Does Java pass by reference or pass by value?”
