java.lang Package : Provides classes that are fundamental to the design of the Java programming language.
Interfaces in java.lang Package
S.No | Interface & Description |
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1 | Appendable
An object to which char sequences and values can be appended.
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2 | AutoCloseable
An object that may hold resources (such as file or socket handles) until it is closed.
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3 | CharSequence
A CharSequence is a readable sequence of char values.
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4 | Cloneable A class implements the Cloneable interface to indicate to the Object.clone() method that it is legal for that method to make a field-for-field copy of instances of that class.
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5 | Comparable<T>
This interface imposes a total ordering on the objects of each class that implements it.
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6 | Iterable<T>
Implementing this interface allows an object to be the target of the "for-each loop" statement.
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7 | Readable
A Readable is a source of characters.
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8 | Runnable
The Runnable interface should be implemented by any class whose instances are intended to be executed by a thread.
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9 | Thread.UncaughtExceptionHandler
Interface for handlers invoked when a Thread abruptly terminates due to an uncaught exception.
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Classes in java.lang Package
S.No | Class & Description |
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1 | Boolean
The Boolean class wraps a value of the primitive type boolean in an object.
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2 | Byte
The Byte class wraps a value of primitive type byte in an object.
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3 | Character
The Character class wraps a value of the primitive type char in an object.
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4 | Character.Subset
Instances of this class represent particular subsets of the Unicode character set.
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5 | Character.UnicodeBlock
A family of character subsets representing the character blocks in the Unicode specification.
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6 | Class<T>
Instances of the class Class represent classes and interfaces in a running Java application.
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7 | ClassLoader
A class loader is an object that is responsible for loading classes.
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8 | ClassValue<T>
Lazily associate a computed value with (potentially) every type.
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9 | Compiler
The Compiler class is provided to support Java-to-native-code compilers and related services.
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10 | Double
The Double class wraps a value of the primitive type double in an object.
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11 | Enum<E extends Enum<E>>
This is the common base class of all Java language enumeration types.
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12 | Float
The Float class wraps a value of primitive type float in an object.
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13 | InheritableThreadLocal<T>
This class extends ThreadLocal to provide inheritance of values from parent thread to child thread: when a child thread is created, the child receives initial values for all inheritable thread-local variables for which the parent has values.
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14 | Integer
The Integer class wraps a value of the primitive type int in an object.
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15 | Long
The Long class wraps a value of the primitive type long in an object.
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16 | Math
The class Math contains methods for performing basic numeric operations such as the elementary exponential, logarithm, square root, and trigonometric functions.
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17 | Number
The abstract class Number is the superclass of platform classes representing numeric values that are convertible to the primitive types byte, double, float, int, long, and short.
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18 | Object
Class Object is the root of the class hierarchy.
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19 | Package
Package objects contain version information about the implementation and specification of a Java package.
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20 | Process
The ProcessBuilder.start() and Runtime.exec methods create a native process and return an instance of a subclass of Process that can be used to control the process and obtain information about it.
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21 | ProcessBuilder
This class is used to create operating system processes.
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22 | ProcessBuilder.Redirect
Represents a source of subprocess input or a destination of subprocess output.
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23 | 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.
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24 | RuntimePermission
This class is for runtime permissions.
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25 | SecurityManager
The security manager is a class that allows applications to implement a security policy.
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26 | Short
The Short class wraps a value of primitive type short in an object.
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27 | StackTraceElement
An element in a stack trace, as returned by Throwable.getStackTrace().
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28 | StrictMath
The class StrictMath contains methods for performing basic numeric operations such as the elementary exponential, logarithm, square root, and trigonometric functions.
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29 | String
The String class represents character strings.
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30 | StringBuffer
A thread-safe, mutable sequence of characters.
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31 | StringBuilder
A mutable sequence of characters.
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32 | System
The System class contains several useful class fields and methods.
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33 | Thread
A thread is a thread of execution in a program.
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34 | ThreadGroup
A thread group represents a set of threads.
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35 | ThreadLocal<T>
This class provides thread-local variables.
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36 | Throwable
The Throwable class is the superclass of all errors and exceptions in the Java language.
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37 | Void
The Void class is an uninstantiable placeholder class to hold a reference to the Class object representing the Java keyword void.
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Enums in java.lang Package
S.No | Enum & Description |
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1 | Character.UnicodeScript
A family of character subsets representing the character scripts defined in the Unicode Standard Annex #24: Script Names.
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2 | ProcessBuilder.Redirect.Type
The type of a ProcessBuilder.Redirect.
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3 | Thread.State
A thread state.
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Exception Classes in java.lang Package
S.No | Exception Class & Description |
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1 | ArithmeticException
Thrown when an exceptional arithmetic condition has occurred.
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2 | ArrayIndexOutOfBoundsException
Thrown to indicate that an array has been accessed with an illegal index.
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3 | ArrayStoreException
Thrown to indicate that an attempt has been made to store the wrong type of object into an array of objects.
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4 | ClassCastException
Thrown to indicate that the code has attempted to cast an object to a subclass of which it is not an instance.
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5 | ClassNotFoundException
Thrown when an application tries to load in a class through its string name using: The forName method in class Class.
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6 | CloneNotSupportedException
Thrown to indicate that the clone method in class Object has been called to clone an object, but that the object’s class does not implement the Cloneable interface.
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7 | EnumConstantNotPresentException
Thrown when an application tries to access an enum constant by name and the enum type contains no constant with the specified name.
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8 | Exception
The class Exception and its subclasses are a form of Throwable that indicates conditions that a reasonable application might want to catch.
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9 | IllegalAccessException
An IllegalAccessException is thrown when an application tries to reflectively create an instance (other than an array), set or get a field, or invoke a method, but the currently executing method does not have access to the definition of the specified class, field, method or constructor.
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10 | IllegalArgumentException
Thrown to indicate that a method has been passed an illegal or inappropriate argument.
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11 | 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.
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12 | IllegalStateException
Signals that a method has been invoked at an illegal or inappropriate time.
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13 | IllegalThreadStateException
Thrown to indicate that a thread is not in an appropriate state for the requested operation.
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14 | 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.
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15 | 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.
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16 | InterruptedException
Thrown when a thread is waiting, sleeping, or otherwise occupied, and the thread is interrupted, either before or during the activity.
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17 | NegativeArraySizeException
Thrown if an application tries to create an array with negative size.
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18 | NoSuchFieldException
Signals that the class doesn’t have a field of a specified name.
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19 | NoSuchMethodException
Thrown when a particular method cannot be found.
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20 | NullPointerException
Thrown when an application attempts to use null in a case where an object is required.
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21 | 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.
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22 | ReflectiveOperationException
Common superclass of exceptions thrown by reflective operations in core reflection.
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23 | RuntimeException
RuntimeException is the superclass of those exceptions that can be thrown during the normal operation of the Java Virtual Machine.
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24 | SecurityException
Thrown by the security manager to indicate a security violation.
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25 | StringIndexOutOfBoundsException
Thrown by String methods to indicate that an index is either negative or greater than the size of the string.
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26 | TypeNotPresentException
Thrown when an application tries to access a type using a string representing the type’s name, but no definition for the type with the specified name can be found.
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27 | UnsupportedOperationException
Thrown to indicate that the requested operation is not supported.
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Error Classes in java.lang Package
S.No | Error Class & Description |
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1 | AbstractMethodError
Thrown when an application tries to call an abstract method.
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2 | AssertionError
Thrown to indicate that an assertion has failed.
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3 | BootstrapMethodError
Thrown to indicate that an invokedynamic instruction has failed to find its bootstrap method, or the bootstrap method has failed to provide a call site with a target of the correct method type.
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4 | ClassCircularityError
Thrown when the Java Virtual Machine detects a circularity in the superclass hierarchy of a class being loaded.
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5 | ClassFormatError
Thrown when the Java Virtual Machine attempts to read a class file and determines that the file is malformed or otherwise cannot be interpreted as a class file.
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6 | Error
An Error is a subclass of Throwable that indicates serious problems that a reasonable application should not try to catch.
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7 | ExceptionInInitializerError
Signals that an unexpected exception has occurred in a static initializer.
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8 | IllegalAccessError
Thrown if an application attempts to access or modify a field, or to call a method that it does not have access to.
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9 | IncompatibleClassChangeError
Thrown when an incompatible class change has occurred to some class definition.
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10 | InstantiationError
Thrown when an application tries to use the Java new construct to instantiate an abstract class or an interface.
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11 | InternalError
Thrown to indicate some unexpected internal error has occurred in the Java Virtual Machine.
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12 | LinkageError
Subclasses of LinkageError indicate that a class has some dependency on another class; however, the latter class has incompatibly changed after the compilation of the former class.
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13 | NoClassDefFoundError
Thrown if the Java Virtual Machine or a ClassLoader instance 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.
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14 | NoSuchFieldError
Thrown if an application tries to access or modify a specified field of an object, and that object no longer has that field.
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15 | NoSuchMethodError
Thrown if an application tries to call a specified method of a class (either static or instance), and that class no longer has a definition of that method.
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16 | 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.
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17 | StackOverflowError
Thrown when a stack overflow occurs because an application recurses too deeply.
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18 | ThreadDeath
An instance of ThreadDeath is thrown in the victim thread when the (deprecated) Thread.stop() method is invoked.
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19 | UnknownError
Thrown when an unknown but serious exception has occurred in the Java Virtual Machine.
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20 | UnsatisfiedLinkError
Thrown if the Java Virtual Machine cannot find an appropriate native-language definition of a method declared native.
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21 | UnsupportedClassVersionError
Thrown when the Java Virtual Machine attempts to read a class file and determines that the major and minor version numbers in the file are not supported.
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22 | VerifyError
Thrown when the "verifier" detects that a class file, though well formed, contains some sort of internal inconsistency or security problem.
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23 | VirtualMachineError
Thrown to indicate that the Java Virtual Machine is broken or has run out of resources necessary for it to continue operating.
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