Java glossary: Journeyman level
57 Java terms at the Journeyman level, each with a short definition and a link to its full page.
Updated
- Aggregation
- A relationship where one object uses another object that can exist independently.
- Annotation
- A way of marking a method so that the runtime knows to use it a certain way..
- Assertion
- A development-time check that reports when an expected condition is false.
- AssertJ
- A Java library that gives Java fluent, readable assertions.
- Association
- A general relationship in which objects know about or work with one another.
- Buffered Reader
- A reader that buffers characters so text can be read efficiently.
- catch Block
- A block that handles a matching exception from its try block.
- Checked Exception
- An exception the compiler requires code to catch or declare.
- Composition
- Building a class from other objects that handle parts of its work.
- Constructor
- Special class code that initializes a new object.
- Constructor Chaining
- Calling another constructor so initialization logic can be reused.
- Custom Exception
- An application-specific exception type created by extending an exception class.
- Default Constructor
- A no-argument constructor supplied by the compiler when a class declares none.
- Default Method
- An interface method with an implementation inherited by implementing classes.
- Dynamic Dispatch
- Choosing an overridden instance method at runtime from the object's actual class.
- Encapsulation
- Keeping an object's data behind methods that control how it is read or changed.
- Exception
- An object describing a problem that interrupts normal program flow.
- Exception Handling
- Using try, catch, and related statements to respond to failures.
- Field
- A variable declared in a class and stored with an object or the class itself.
- File
- A filesystem path together with operations for inspecting or managing it.
- File Input/Output
- Reading data from files and writing data to files.
- finally Block
- A block that normally runs after try and catch whether an exception occurred or not.
- Getter
- A method that returns an object's stored value.
- hashCode()
- A method that produces an integer used by hash-based collections.
- Inheritance
- Creating a class that receives accessible members from another class.
- Instance
- A particular object created from a class.
- instanceof
- An operator that tests whether an object is compatible with a given type.
- Interface
- A contract describing behavior that implementing classes agree to provide.
- java.nio.file
- The package containing modern APIs for paths, files, directories, and file operations.
- Method Overriding
- Providing a subclass version of an inherited instance method.
- Mockito
- The standard Java library for mocking objects for unit tests.
- Multiple Inheritance
- Inheriting from more than one parent type, supported in Java through interfaces rather than classes.
- new Keyword
- An operator that creates an object or array and returns its reference.
- Object
- A class instance that combines its own state with available behavior.
- Object Class
- The root class from which every Java class ultimately inherits.
- Object Equality
- The rules that decide when two objects should count as having the same value.
- Package-Private Access
- The default access that limits a type or member to its package.
- Path
- A modern Java representation of a location in a filesystem.
- Polymorphism
- Using one declared type to work with objects that provide different implementations.
- private
- An access modifier that limits a member to its declaring top-level class.
- protected
- An access modifier that permits package access and access through subclasses.
- public
- An access modifier that makes a type or member broadly accessible.
- Reference Variable
- A variable that stores a reference to an object rather than the object itself.
- Serialization
- Converting an object's state into data that can be stored or transferred.
- Setter
- A method that validates or changes an object's stored value.
- Stack Trace
- A report showing the active method calls at the point an error occurred.
- Static Interface Method
- A utility method that belongs to an interface rather than its implementations.
- Subclass
- A class that extends another class.
- super
- A reference used to access a superclass constructor or member.
- Superclass
- The class that another class directly extends.
- this
- A reference to the current object inside its instance code.
- throw
- A statement that deliberately raises an exception object.
- throws
- A method declaration clause listing exceptions callers may need to handle.
- toString()
- A method that returns a readable text representation of an object.
- transient
- A field modifier that excludes the field from Java's default serialization.
- try Block
- A block containing code that may throw an exception.
- Unchecked Exception
- A runtime exception the compiler does not require code to catch or declare.