JavaLangException

javalangException is not a standard class in the Java Platform, API. It does not appear in the official Java SE libraries, and the exact name is not used by the Java runtime. The term is most likely a misspelling, a truncated reference to java.lang.Exception, or the name of a custom exception defined within a specific project.

In Java, exceptions are objects that signal error conditions and are organized in a hierarchy beginning with java.lang.Throwable. The base checked exception is java.lang.Exception, while java.lang.RuntimeException is the base class for unchecked exceptions. If a codebase mentions javalangException, it probably refers to a user-defined exception or is simply a mistaken reference to java.lang.Exception.

When encountered in code, determine the actual type by searching for its declaration, import statements, and how it is used in catch blocks. If no declaration exists, it is a typo. If a declaration exists, it is a custom exception that should follow standard conventions for exceptions in Java: extending Exception or RuntimeException, providing meaningful constructors, and documenting its purpose.

Design considerations for a custom exception include choosing the right base class (checked vs unchecked), including serialVersionUID if the class implements Serializable, and providing constructors with messages and causes to aid debugging. A well-named class helps readability; common practice uses names that clearly describe the error condition, such as InvalidConfigurationException or JavaLangException if the intent is to model language-related errors.

See also Java exception handling, java.lang.Exception, checked exceptions, unchecked exceptions, and custom exceptions in Java.