The JMatch language extends Java with support for abstract iterable pattern matching: a mechanism for pattern matching that is compatible with the data abstraction features of Java and also makes iteration abstractions convenient to use and to implement. JMatch provides abstract pattern matching; patterns are not tied to algebraic data constructors as in ML. A single JMatch method may be used in several modes that may share a common implementation as a boolean formula. JMatch provides modal abstraction that simplifies the specification and implementation of abstract data types. JMatch also makes the specification, implementation, and use of iteration abstractions convenient, by automatically finding multiple solutions to a formula or pattern.