When their is method name and method body then it is called Concreate Method or Complete Method.

Example

public class Animal
{		
		public void cal()// method name
		{
				int max = 0;//method body
		}
}

When their is method with only method name then it is called abstract method. In simple words abstract means incomplete.

Example

abstract public class Animal //if there is single abstact method present then we have to make the whole class abstract
{		
		abstract public void cal();//only method name is attached with abstact keyword
}

public class Dog extends Animal{
		public void cal(){
				// body
				cal(){
						 System.out.println("hello, Ji");
		}
		public static void main(String[] args){
				Dog d = new Dog();
				d.cal()
		}
}

Object of abstract class can be created by calling the child constructor while initializing.

abstract public class Animal //if there is single abstact method present then we have to make the whole class abstract
{		
		abstract public void cal();//only method name is attached with abstact keyword
}

public class Dog extends Animal{
		public void cal(){
				// body
				cal(){
						 System.out.println("hello, Ji");
		}
		public static void main(String[] args){
				Animal a = new Dog();
				a.cal()
		}
}

Note

1. If there is single abstract method present then we have to make the whole class abstract.
2. Abstract class cannot be instantiated because it is an incomplete class.
3. When we declare any child class of abstract class then to use the class we have fulfill all the abstract method present in the parent or else keep the child abstract too.