Class Objects

java.lang.Object

java.util.Objects

public final class Objects
extends Object

This is a compatibility class which supports the java.util.Objects API. On platforms that don't support this class (e.g. Android) the build server will automatically remap all uses of java.util.Objects to use this implementation instead.

This class consists of static utility methods for operating on objects. These utilities include null-safe or null-tolerant methods for computing the hash code of an object, returning a string for an object, and comparing two objects.

Method Summary

Modifier and Type	Method	Description
static int	checkFromIndexSize(int fromIndex, int size, int length)	fromIndex, if [fromIndex, fromIndex + size) lies in [0, length).
static long	checkFromIndexSize(long fromIndex, long size, long length)	fromIndex, if [fromIndex, fromIndex + size) lies in [0, length).
static int	checkFromToIndex(int fromIndex, int toIndex, int length)	fromIndex, if [fromIndex, toIndex) lies in [0, length).
static long	checkFromToIndex(long fromIndex, long toIndex, long length)	fromIndex, if [fromIndex, toIndex) lies in [0, length).
static int	checkIndex(int index, int length)	index, if it lies in [0, length).
static long	checkIndex(long index, long length)	index, if it lies in [0, length).
static <T> int	compare(T a, T b, Comparator<? super T> c)
static boolean	deepEquals(Object a, Object b)
static boolean	equals(Object a, Object b)	Returns true if the arguments are equal to each other and false otherwise.
static int	hash(Object... values)
static int	hashCode(Object o)	Returns the hash code of a non-null argument and 0 for a null argument.
static boolean	isNull(Object obj)	Whether obj is null.
static boolean	nonNull(Object obj)
static <T> T	requireNonNull(T obj)
static <T> T	requireNonNull(T obj, String message)
static <T> T	requireNonNull(T obj, Supplier<String> messageSupplier)	obj, or a NullPointerException whose message messageSupplier makes, only when it is needed.
static <T> T	requireNonNullElse(T obj, T defaultObj)	obj, or defaultObj when obj is null.
static <T> T	requireNonNullElseGet(T obj, Supplier<? extends T> supplier)	obj, or what supplier gives when obj is null.
static String	toIdentityString(Object o)	What Object.toString would answer for o, even when its class overrides it.
static String	toString(Object o)
static String	toString(Object o, String nullDefault)

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

equals

public static boolean equals(Object a,
 Object b)

Returns true if the arguments are equal to each other and false otherwise. Consequently, if both arguments are null, true is returned and if exactly one argument is null, false is returned. Otherwise, equality is determined by using the equals method of the first argument.

Parameters

• a

• b

hashCode

public static int hashCode(Object o)

Returns the hash code of a non-null argument and 0 for a null argument.

Parameters

• o

toString

public static String toString(Object o)

toString

public static String toString(Object o,
 String nullDefault)

compare

public static <T> int compare(T a,
 T b,
 Comparator<? super T> c)

requireNonNull

public static <T> T requireNonNull(T obj)

requireNonNull

public static <T> T requireNonNull(T obj,
 String message)

nonNull

public static boolean nonNull(Object obj)

deepEquals

public static boolean deepEquals(Object a,
 Object b)

hash

public static int hash(Object... values)

isNull

public static boolean isNull(Object obj)

Whether obj is null.

requireNonNull

public static <T> T requireNonNull(T obj,
 Supplier<String> messageSupplier)

obj, or a NullPointerException whose message messageSupplier makes, only when it is needed.

requireNonNullElse

public static <T> T requireNonNullElse(T obj,
 T defaultObj)

obj, or defaultObj when obj is null.

Throws

• NullPointerException: if both are null

requireNonNullElseGet

public static <T> T requireNonNullElseGet(T obj,
 Supplier<? extends T> supplier)

obj, or what supplier gives when obj is null.

Throws

• NullPointerException: if obj is null and the supplier is null or gives null

checkIndex

public static int checkIndex(int index,
 int length)

index, if it lies in [0, length).

Throws

• IndexOutOfBoundsException: otherwise

checkIndex

public static long checkIndex(long index,
 long length)

index, if it lies in [0, length).

checkFromToIndex

public static int checkFromToIndex(int fromIndex,
 int toIndex,
 int length)

fromIndex, if [fromIndex, toIndex) lies in [0, length).

checkFromToIndex

public static long checkFromToIndex(long fromIndex,
 long toIndex,
 long length)

fromIndex, if [fromIndex, toIndex) lies in [0, length).

checkFromIndexSize

public static int checkFromIndexSize(int fromIndex,
 int size,
 int length)

fromIndex, if [fromIndex, fromIndex + size) lies in [0, length).

checkFromIndexSize

public static long checkFromIndexSize(long fromIndex,
 long size,
 long length)

fromIndex, if [fromIndex, fromIndex + size) lies in [0, length).

toIdentityString

public static String toIdentityString(Object o)

What Object.toString would answer for o, even when its class overrides it.