''EditHint: Move stuff on this topic from ConstCorrectness to here.''

I appreciate ConstCorrectness enormously and miss it sorely in JavaLanguage. :-(

''Some languages have RunTime constantness, with ''freeze'' and ''thaw''. Do they allow ''thaw'' when running in a secure mode?''
* Is that something like InterCal's ''snub'' and ''apologize''?

Do ''freeze'' and ''thaw'' act on the object or the object reference?

----
Given...

   Object nonConst; 
   Object const Const; 
   Object const & constRef = nonConst; 

   nonConst.foo();  //  <-- calls foo() (non-const) if available 
   Const.foo();     //  <-- must call foo() const 
   constRef.foo();  //  <-- must call foo() const
...note that constancy is a form of encapsulation. Both the Const object and the constRef make their Object more encapsulated - meaning potentially safer and more robust - than the non-constant versions. So "const-correct" code generally extends more usages to constant things than to changeable things. 

----
More literally:

 interface FooConst{
	int readX();
	int readY();
 }
 abstract class Foo implements FooConst{
	abstract public int readX(); 
	abstract public int readY(); 
	abstract public int writeX(int value); 
	abstract public int writeY(int value); 
 }

Methods that want a "const Foo" parameter need only declare a FooConst as their argument.