An item of data named by an identifier. Each variable has a type, such as int or Object, and a scope. See also class variable, instancevariable, local variable.
An abstract specification for a computing device that can be implemented in different ways, in software or hardware. You compile to the instruction set of a virtual machine much like you'd compile to the instruction set of a microprocessor. The Java virtual machine consists of a bytecode instruction set, a set of registers, a stack, a garbage-collected heap, and an area for storing methods.
A Java keyword used in method declarations to specify that the method does not return any value. void can also be used as a nonfunctional statement.
A class or interface.
A Java keyword used in variable declarations that specifies that the variable is modified asynchronously by concurrently running threads