A Java lambda expression is an anonymous method.
The Java lambda method implements a method defined by a functional interface.
A lambda expression results in a form of anonymous class.
Lambda expressions are commonly referred to as closures.
A functional interface is an interface with one and only one abstract method.
The lambda expression introduces a new operator into the Java language.
The new operator is ->.
The left side of the -> specifies parameters required by the lambda expression.
If no parameters are needed, an empty parameter list is used.
On the right side of -> is the lambda body.
The lambda specifies the actions of the lambda expression.
Java has two types of lambda bodies:
For example, the following lambda expression:
() -> 123.45
This lambda expression takes no parameters, thus the parameter list is empty.
It returns the constant value 123.45.
It is similar to the following method:
double myMeth() { return 123.45; }