Java Operators: String Concatenation, Relational, Equality, instanceof & Bitwise — Complete Guide Java Operators +   <   ==   instanceof   &   |   ^   ~   ! [ thumbnail placeholder ] Java Operators: String Concatenation, Relational, Equality, instanceof & Bitwise This post covers the operators that most often trip people up in Java: + (concatenation), relational and equality operators, instanceof , the bitwise operators & | ^ , and the two complement operators ~ and ! . Each section has examples with outputs and the compile errors you should expect. Operator Works on Result + numbers, or any operand when one side is a String sum, or String < <= > >= numeric primitives (and their wrappers) boolean == != any primitive, or object references boolean instanceof object reference + class/interface boolean & | ^ boolean or integral boolean or integral ~ integral only integral ! boolean...