Package java.lang

Package
java.lang

Description
Provides classes that are fundamental to the Java programming language.

Class Summary


Interfaces
Runnable The Runnable interface should be implemented by any class whose instances are
intended to be executed by a thread.
Classes
Boolean The Boolean class wraps a value of the primitive type boolean in an object.
Byte The Byte class is the standard wrapper for byte values.
Character The Character class wraps a value of the primitive type char in an object.
Class Instances of the class Class represent classes and interfaces in a running Java
application.
Double The Double class wraps a value of the primitive type double in an object.
Float The Float class wraps a value of primitive type float in an object.
Integer The Integer class wraps a value of the primitive type int in an object.
Long The Long class wraps a value of the primitive type long in an object.
Math The class Math contains methods for performing basic numeric operations.
Object Class Object is the root of the class hierarchy.
Runtime Every Java application has a single instance of class Runtime that allows the
application to interface with the environment in which the application is running.
Short The Short class is the standard wrapper for short values.
String The String class represents character strings.
StringBuffer A string buffer implements a mutable sequence of characters.
System The System class contains several useful class fields and methods.
Thread A thread is a thread of execution in a program.
Throwable The Throwable class is the superclass of all errors and exceptions in the Java
language.



Exceptions
ArithmeticException Thrown when an exceptional arithmetic condition has occurred.
ArrayIndexOutOfBoundsE
xception
Thrown to indicate that an array has been accessed with an illegal index.
ArrayStoreException Thrown to indicate that an attempt has been made to store the wrong type of object into
an array of objects.
ClassCastException Thrown to indicate that the code has attempted to cast an object to a subclass of which
it is not an instance.
ClassNotFoundException Thrown when an application tries to load in a class through its string name using the
forName method in class Class but no definition for the class with the specified
name could be found.
Exception The class Exception and its subclasses are a form of Throwable that indicates
conditions that a reasonable application might want to catch.
IllegalAccessException Thrown when an application tries to load in a class, but the currently executing method
does not have access to the definition of the specified class, because the class is not
public and in another package.
IllegalArgumentExcepti
on
Thrown to indicate that a method has been passed an illegal or inappropriate argument.
IllegalMonitorStateExc
eption
Thrown to indicate that a thread has attempted to wait on an object’s monitor or to
notify other threads waiting on an object’s monitor without owning the specified
monitor.
IllegalThreadStateExce
ption
Thrown to indicate that a thread is not in an appropriate state for the requested
operation.
IndexOutOfBoundsExcept
ion
Thrown to indicate that an index of some sort (such as to an array, to a string, or to a
vector) is out of range.
InstantiationException Thrown when an application tries to create an instance of a class using the
newInstance method in class Class, but the specified class object cannot be
instantiated because it is an interface or is an abstract class.
InterruptedException Thrown when a thread is waiting, sleeping, or otherwise paused for a long time and
another thread interrupts it.
NegativeArraySizeExcep
tion
Thrown if an application tries to create an array with negative size.
NullPointerException Thrown when an application attempts to use null in a case where an object is
required.
NumberFormatException Thrown to indicate that the application has attempted to convert a string to one of the
numeric types, but that the string does not have the appropriate format.
RuntimeException RuntimeException is the superclass of those exceptions that can be thrown during
the normal operation of the Java Virtual Machine.
SecurityException Thrown by the system to indicate a security violation.
StringIndexOutOfBounds
Exception
Thrown by the charAt method in class String and by other String methods to
indicate that an index is either negative or greater than or equal to the size of the string.
Errors



Error An Error is a subclass of Throwable that indicates serious problems that a
reasonable application should not try to catch.
NoClassDefFoundError Thrown if the Java Virtual Machine tries to load in the definition of a class (as part of a
normal method call or as part of creating a new instance using the new expression) and
no definition of the class could be found.
OutOfMemoryError Thrown when the Java Virtual Machine cannot allocate an object because it is out of
memory, and no more memory could be made available by the garbage collector.
VirtualMachineError Thrown to indicate that the Java Virtual Machine is broken or has run out of resources
necessary for it to continue operating.