is there a list of de-facto immutable classes in the jdk?
technically Immutable classes include the obvious Integer, Double etc..
de-facto immutable will include for example java.lang.String - it might technically be mutable but de-facto it is not.
Also, are there Interfaces/Abstract classes which are required (as stated in the javadoc) to be immutable?
if you cannot provide a complete List, i would already be happy if you know a bunch of classes which state immutability in its javadoc..
Classes whose object contents cannot be modified is called immutable classes. All primitive data types(Wrapper classes only) are immutable. For any class to be immutable the following needs to be done.