In Java, the keyword "this" refers to the current object of a method or constructor. It is used to refer to the instance variables and methods of the current object from within the objects own methods. The most common use of the "this" keyword is to eliminate the confusion between class attributes and parameters that have the same names. Here are some of the uses of the "this" keyword in Java:

• It can be used to refer to the instance variable of the current class.
• It can be used to invoke or initiate the current class constructor.
• It can be passed as an argument in the method call.
• It can be passed as an argument in the constructor call.
• It can be used to return the current class instance.

When used in constructors or instance methods, "this" is a reference to the current object, which is the object whose method or constructor is being called. By using "this", you can refer to any member of the current object from within an instance method or a constructor.