Operator overloading in Java (Integer wrapper class)? -

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• is autoboxing possible classes create? 3 answers

i came across example in ocjp book. says

integer y=new integer("20"); y++;   (un-wraps it) system.out.println(y); 

now, print 21. hence, makes me think, how did compiler know @ y++ should unwrap int , increment it? integer normal class(may wrapper class??), operator overloading inbuilt inside?

is there way can own custom class if possible?

java uses feature called autoboxing , unboxing unwrap integer , increment it. cannot implement feature in own user-defined classes. available wrapper classes java primitive types.