An instance variable differs from a local variable in the nature of its scope and its lifetime. The entire class makes up the scope of an instance variable, not the method in which it was declared.

Can have instance mutable fields, parameters, or local variables. Only functional interfaces can use the lambda feature in Java. Abstract classes with only one abstract method cannot use lambdas.

In this article, he dives into Local Variable Type Inference. Java SE 10 (March 2018) introduced type inference for local variables. Java Language Architect Brian Goetz explains the feature. BT.