package

java.lang

Provides classes that are fundamental to the Java programming language.

Interfaces

Appendable Declares methods to append characters or character sequences. 
CharSequence This interface represents an ordered set of characters and defines the methods to probe them. 
Cloneable This (empty) interface must be implemented by all classes that wish to support cloning. 
Comparable<T> This interface should be implemented by all classes that wish to define a natural order of their instances. 
Iterable<T> Objects of classes that implement this interface can be used within a foreach statement. 
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<T> 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. 
Enum<E extends Enum<E>> This is the common base class of all Java language enumeration types. 
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 such as the elementary exponential, logarithm, square root, and trigonometric functions. 
Number The abstract class Number is the superclass of classes Byte, Double, Float, Integer, Long, and Short. 
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. 
StringBuilder 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. 
ArrayIndexOutOfBoundsException 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. 
CloneNotSupportedException Thrown when a program attempts to clone an object which does not support the Cloneable interface. 
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. 
IllegalArgumentException Thrown to indicate that a method has been passed an illegal or inappropriate argument. 
IllegalMonitorStateException 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. 
IllegalStateException Signals that a method has been invoked at an illegal or inappropriate time. 
IllegalThreadStateException Thrown to indicate that a thread is not in an appropriate state for the requested operation. 
IndexOutOfBoundsException 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 using the interrupt method in class Thread. 
NegativeArraySizeException 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 security manager to indicate a security violation. 
StringIndexOutOfBoundsException 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. 
UnsupportedOperationException  

Errors

Error An Error is a subclass of Throwable that indicates serious problems that a reasonable application should not try to catch. 
IncompatibleClassChangeError IncompatibleClassChangeError is the superclass of all classes which represent errors that occur when inconsistent class files are loaded into the same running image. 
LinkageError LinkageError is the superclass of all error classes that occur when loading and linking class files. 
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. 
NoSuchFieldError Thrown when the virtual machine notices that a program tries to reference, on a class or object, a field that does not exist. 
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.