Java 8 new features
Lamda expressions: Provides anonymous function type
One issue with anonymous classes is that if the implementation of your anonymous class is very simple, such as an interface that contains only one method, then the syntax of anonymous classes may seem unwieldy and unclear. In these cases, you're usually trying to pass functionality as an argument to another method, such as what action should be taken when someone clicks a button. Lambda expressions enable you to do this, to treat functionality as method argument, or code as data.
doSomeThing (new DoStuff{
public boolean isGood(int val){
return val == 100;
}
})
changed to lamda expression
doSomeThing = answer -> answer == 100;
Simplified code
Improved usability of Generics
Annotations of Java types
doSomeThing(@notnull List lst)
Streams: A sequence of elements supporting sequential and parallel aggregate operation
The operations cane be series of intermediate followed by terminal operation. Intermediate operations return a stream so we can chain multiple intermediate operations without using semicolons. Terminal operations are either void or return a non-stream result.
Default Methods (multiple inheritance)
Hashmap Performance improvement
They started using tree map instead of linked list and so the searching complexity changed from O(n) to O(log n) in worst case hash keys (all hashcodes are equal resulting all values in single bucket)
