This content originally appeared on DEV Community and was authored by KIRAN RAJ
- What is this keyword in Java?
This is a reference variable in Java.
It refers to the current object (the object whose method or constructor is being executed).
- Where is this used?
You can use this in many places:
To refer to current class instance variables when they are shadowed by method/constructor parameters.
To call current class methods.
To call one constructor from another constructor (constructor chaining).
To return the current class object.
To pass the current object as an argument in method calls or constructors.
- When do we use this?
When local variables (method/constructor parameters) have the same name as instance variables → to avoid confusion.
When you want to chain constructors inside the same class.
When you want to pass the current object to another method/class.
- How do we use this?
- How → Using this.variable, this(), this.method(), return this, method(this).
- Why is this used?
To resolve ambiguity between instance variables and local variables.
To improve code readability and avoid errors.
To allow constructor chaining.
To refer to the current object flexibly.
- What is super?
Super is a reference keyword in Java that refers to the immediate parent class (superclass) of the current object.
It helps to access parent class members (variables, methods, constructors) that are hidden or overridden in the child class.
- Where is super used?
- Inside a child class that extends a parent class.
You can use it:
With variables → to access parent class fields.
With methods → to call parent class methods.
With constructors → to call parent class constructors.
- When is super used?
When the child class has a variable or method with the same name as the parent class (to avoid confusion).
When you need to invoke the parent’s overridden method from the child class.
- How is super used?
If child and parent have the same variable name, use super.variableName to get the parent’s value.
If child overrides a parent’s method, super.methodName() lets you call the parent’s version.
- Why is super?
To avoid ambiguity when the child and parent have the same variable/method.
To reuse parent class logic instead of rewriting it.
This content originally appeared on DEV Community and was authored by KIRAN RAJ