BINARY COMPATIBILITY

The Form of a Java Binary

13.1

confusion at link time. This rule does mean, however, that moving a field to a

superclass is not a binary compatible change; see  13.4.5 for a discussion.)

The reference must also include a symbolic reference to the declared type of

the field so that the verifier can check that the type is as expected. References

to fields that are

static

,

final

, and initialized with compile time constant

expressions are resolved at compile time to the constant value that is denoted.

No reference to such a constant field should be present in the code in a binary

file (except in the class or interface containing the constant field, which will

have code to initialize it), and such constant fields must always appear to have

been initialized; the default initial value for the type of such a field must never

be observed. See  13.4.8 for a discussion.

A reference to a method or constructor must be resolved at compile time to a

symbolic reference to the class or interface in which the denoted method or

constructor is declared, plus the signature of the method or constructor. (As

for fields, this makes the binaries more robust, with the caveat that such a

method cannot be moved to a superclass without leaving a forwarding method

behind; see  13.4.5 for a discussion.) A reference to a method must also

include either a symbolic reference to the return type of the denoted method

or an indication that the denoted method is declared

void

 and does not return

a value. The signature of a method must include all of the following:

N

The simple name of the method

N

The number of parameters to the method

N

A symbolic reference to the type of each parameter

The signature of a constructor must include both:

N

The number of parameters to the constructor

N

A symbolic reference to the type of each parameter

A Java binary representation for a class or interface must also contain all of the

following:

If it is a class and is not class

java.lang.Object

, then a symbolic reference

to the direct superclass of this class

A symbolic reference to each direct superinterface, if any

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