Static vs non-static behavior in Java - Quick Revision & Key Differences

overview

Recall & Review

beginner

What does the static keyword mean in Java?

The <strong>static</strong> keyword means the member belongs to the class itself, not to any specific object. It can be accessed without creating an object.

beginner

How do non-static members behave differently from static members?

Non-static members belong to individual objects. Each object has its own copy, so changes affect only that object.

intermediate

Can a static method access non-static variables directly? Why or why not?

No, a static method cannot access non-static variables directly because non-static variables belong to objects, and static methods belong to the class without any object context.

intermediate

What happens if you try to use this keyword inside a static method?

You cannot use this inside a static method because this refers to the current object, and static methods do not belong to any object.

beginner

Give a real-life example to explain static vs non-static behavior.

Think of a school: The school name is static because it is the same for all students (objects). Each student has their own name and grades, which are non-static because they differ per student.

Which of the following is true about static variables in Java?

A They can only be accessed through objects.

B They belong to each object separately.

C They belong to the class and are shared by all objects.

D They cannot be accessed inside static methods.

Can a non-static method access static variables directly?

A No, it cannot access static variables.

B Only if the static variable is public.

C Only if the method is called from a static context.

D Yes, because static variables belong to the class.

What will happen if you try to access a non-static variable inside a static method without an object?

A It will work fine.

B It will cause a compile-time error.

C It will cause a runtime error.

D It will print default values.

Which keyword is used to declare a static method in Java?

A static

B final

C public

D void

If you want a variable to be unique for each object, how should you declare it?

A non-static (instance variable)

B final

C static

D abstract

Explain the difference between static and non-static members in Java with examples.

Describe why static methods cannot use the 'this' keyword and what that means for accessing variables.