A class which is declared with the abstract keyword is known as an abstract class in Java. It can have abstract and non-abstract methods (method with the body). code example

Example 1: What are abstract methods in java

An abstract method is the method which does’nt have any body. 
Abstract method is declared with
keyword abstract and semicolon in place of method body.

  public abstract void <method name>();
Ex : public abstract void getDetails();
It is the responsibility of subclass to provide implementation to 
abstract method defined in abstract class

Example 2: can abstract class have non abstract methods in java

abstract class AbstractDemo { // Abstract class
   private int i = 0;
   public void display() { // non-abstract method
      System.out.print("Welcome to Tutorials Point");
   }
}
public class InheritedClassDemo extends AbstractDemo {
   public static void main(String args[]) {
      AbstractDemo demo = new InheritedClassDemo();
      demo.display();
   }
}