JDK8 default Methods

1. Default Methods

2. Default Methods
 Why do we need default methods ?
 Usage
 Abstract Classes vs Interface with default methods

3. Why do we need default methods ?
Public void apply()
Public void apply(){}
Public void apply(){}
Public void apply(){}
Interface-v0
Class
Class
Class
Public void apply()
Public void execute()
Public void apply(){}
Public void execute(){}
Public void apply(){}
Public void execute(){}
Public void apply(){}
Public void execute(){}
Interface-v1
Class
Class
Class

4. Usage

5. Resolution Rules
 Classes always win
Default void apply(){}
void apply(){}
Interface A
Class B implements A
New c().apply()

6. Resolution Rules
 sub-interfaces wins
Default void apply(){}
Interface A
Class C implements B
Default void apply(){}
Interface B extends ANew c().apply()

7. Resolution Rules
 Ambiguous
Default void apply(){}
Interface A
Class C implements A,B
Default void apply(){}
Interface B
New c().apply()