13.4.13

Method and Constructor Parameters

BINARY COMPATIBILITY

should have as much or more access if compatibility with pre existing binaries is

to be preserved.

13.4.13   Method and Constructor Parameters

Changing the name of a formal parameter of a method or constructor does not

impact pre existing binaries. Changing the name of a method, the type of a formal

parameter to a method or constructor, or adding a parameter to or deleting a

parameter from a method or constructor declaration creates a method or construc 

tor with a new signature, and has the combined effect of deleting the method or

constructor with the old signature and adding a method or constructor with the

new signature (see  13.4.12).

13.4.14   Method Result Type

Changing the result type of a method, replacing a result type with

void

, or replac 

ing

void

 with a result type has the combined effect of deleting the old method or

constructor and adding a new method or constructor with the new result type or

newly

void

 result (see  13.4.12).

13.4.15

abstract

Methods

Changing a method that is declared

abstract

 to no longer be declared

abstract

does not break compatibility with pre existing binaries.

Changing a method that is not declared

abstract

 to be declared

abstract

will break compatibility with pre existing binaries that previously invoked the

method, causing an

AbstractMethodError

. If the example program:

class Super { void out() { System.out.println("Out"); } }

class Test extends Super {

public static void main(String[] args) {

Test t = new Test();

System.out.println("Way ");

t.out();

}

}

is compiled and executed, it produces the output:

Way

Out

Suppose that a new version of class

Super

 is produced:

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