ObjectUtils

java.lang.Object
- org.springframework.util.ObjectUtils

```
public abstract class ObjectUtils
extends java.lang.Object
```
Miscellaneous object utility methods.
Mainly for internal use within the framework.
Thanks to Alex Ruiz for contributing several enhancements to this class!

Since:

19.03.2004

Author:

Juergen Hoeller, Keith Donald, Rod Johnson, Rob Harrop, Chris Beams, Sam Brannen

See Also:

ClassUtils, CollectionUtils, StringUtils

Field Summary

Fields
Modifier and Type	Field and Description
`private static java.lang.String`	`ARRAY_ELEMENT_SEPARATOR`
`private static java.lang.String`	`ARRAY_END`
`private static java.lang.String`	`ARRAY_START`
`private static java.lang.String`	`EMPTY_ARRAY`
`private static java.lang.String`	`EMPTY_STRING`
`private static int`	`INITIAL_HASH`
`private static int`	`MULTIPLIER`
`private static java.lang.String`	`NULL_STRING`

Constructor Summary

Constructors
Constructor and Description

ObjectUtils()

Constructors
Constructor and Description
`ObjectUtils()`

Method Summary

All Methods Static Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`static <A,O extends A> A[]`	`addObjectToArray(A[] array, O obj)` Append the given object to the given array, returning a new array consisting of the input array contents plus the given object.
`private static boolean`	`arrayEquals(java.lang.Object o1, java.lang.Object o2)` Compare the given arrays with `Arrays.equals`, performing an equality check based on the array elements rather than the array reference.
`static <E extends java.lang.Enum<?>> E`	`caseInsensitiveValueOf(E[] enumValues, java.lang.String constant)` Case insensitive alternative to `Enum.valueOf(Class, String)`.
`static boolean`	`containsConstant(java.lang.Enum<?>[] enumValues, java.lang.String constant)` Check whether the given array of enum constants contains a constant with the given name, ignoring case when determining a match.
`static boolean`	`containsConstant(java.lang.Enum<?>[] enumValues, java.lang.String constant, boolean caseSensitive)` Check whether the given array of enum constants contains a constant with the given name.
`static boolean`	`containsElement(java.lang.Object[] array, java.lang.Object element)` Check whether the given array contains the given element.
`static java.lang.String`	`getDisplayString(java.lang.Object obj)` Return a content-based String representation if `obj` is not `null`; otherwise returns an empty String.
`static java.lang.String`	`getIdentityHexString(java.lang.Object obj)` Return a hex String form of an object's identity hash code.
`static int`	`hashCode(boolean bool)` Deprecated. as of Spring Framework 5.0, in favor of the native JDK 8 variant
`static int`	`hashCode(double dbl)` Deprecated. as of Spring Framework 5.0, in favor of the native JDK 8 variant
`static int`	`hashCode(float flt)` Deprecated. as of Spring Framework 5.0, in favor of the native JDK 8 variant
`static int`	`hashCode(long lng)` Deprecated. as of Spring Framework 5.0, in favor of the native JDK 8 variant
`static java.lang.String`	`identityToString(java.lang.Object obj)` Return a String representation of an object's overall identity.
`static boolean`	`isArray(java.lang.Object obj)` Determine whether the given object is an array: either an Object array or a primitive array.
`static boolean`	`isCheckedException(java.lang.Throwable ex)` Return whether the given throwable is a checked exception: that is, neither a RuntimeException nor an Error.
`static boolean`	`isCompatibleWithThrowsClause(java.lang.Throwable ex, java.lang.Class<?>... declaredExceptions)` Check whether the given exception is compatible with the specified exception types, as declared in a throws clause.
`static boolean`	`isEmpty(java.lang.Object obj)` Determine whether the given object is empty.
`static boolean`	`isEmpty(java.lang.Object[] array)` Determine whether the given array is empty: i.e.
`static java.lang.String`	`nullSafeClassName(java.lang.Object obj)` Determine the class name for the given object.
`static boolean`	`nullSafeEquals(java.lang.Object o1, java.lang.Object o2)` Determine if the given objects are equal, returning `true` if both are `null` or `false` if only one is `null`.
`static int`	`nullSafeHashCode(boolean[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(byte[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(char[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(double[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(float[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(int[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(long[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(java.lang.Object obj)` Return as hash code for the given object; typically the value of `Object#hashCode()`}.
`static int`	`nullSafeHashCode(java.lang.Object[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(short[] array)` Return a hash code based on the contents of the specified array.
`static java.lang.String`	`nullSafeToString(boolean[] array)` Return a String representation of the contents of the specified array.
`static java.lang.String`	`nullSafeToString(byte[] array)` Return a String representation of the contents of the specified array.
`static java.lang.String`	`nullSafeToString(char[] array)` Return a String representation of the contents of the specified array.
`static java.lang.String`	`nullSafeToString(double[] array)` Return a String representation of the contents of the specified array.
`static java.lang.String`	`nullSafeToString(float[] array)` Return a String representation of the contents of the specified array.
`static java.lang.String`	`nullSafeToString(int[] array)` Return a String representation of the contents of the specified array.
`static java.lang.String`	`nullSafeToString(long[] array)` Return a String representation of the contents of the specified array.
`static java.lang.String`	`nullSafeToString(java.lang.Object obj)` Return a String representation of the specified Object.
`static java.lang.String`	`nullSafeToString(java.lang.Object[] array)` Return a String representation of the contents of the specified array.
`static java.lang.String`	`nullSafeToString(short[] array)` Return a String representation of the contents of the specified array.
`static java.lang.Object[]`	`toObjectArray(java.lang.Object source)` Convert the given array (which may be a primitive array) to an object array (if necessary of primitive wrapper objects).
`static java.lang.Object`	`unwrapOptional(java.lang.Object obj)` Unwrap the given object which is potentially a `Optional`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - INITIAL_HASH
```
private static final int INITIAL_HASH
```
    See Also:
    
    Constant Field Values
  - MULTIPLIER
```
private static final int MULTIPLIER
```
    See Also:
    
    Constant Field Values
  - EMPTY_STRING
```
private static final java.lang.String EMPTY_STRING
```
    See Also:
    
    Constant Field Values
  - NULL_STRING
```
private static final java.lang.String NULL_STRING
```
    See Also:
    
    Constant Field Values
  - ARRAY_START
```
private static final java.lang.String ARRAY_START
```
    See Also:
    
    Constant Field Values
  - ARRAY_END
```
private static final java.lang.String ARRAY_END
```
    See Also:
    
    Constant Field Values
  - EMPTY_ARRAY
```
private static final java.lang.String EMPTY_ARRAY
```
    See Also:
    
    Constant Field Values
  - ARRAY_ELEMENT_SEPARATOR
```
private static final java.lang.String ARRAY_ELEMENT_SEPARATOR
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - ObjectUtils
```
public ObjectUtils()
```
- Method Detail
  - isCheckedException
```
public static boolean isCheckedException(java.lang.Throwable ex)
```
    Return whether the given throwable is a checked exception: that is, neither a RuntimeException nor an Error.
    
    Parameters:
    
    ex - the throwable to check
    
    Returns:
    
    whether the throwable is a checked exception
    
    See Also:
    
    Exception, RuntimeException, Error
  - isCompatibleWithThrowsClause
```
public static boolean isCompatibleWithThrowsClause(java.lang.Throwable ex,
                                                   @Nullable
                                                   java.lang.Class<?>... declaredExceptions)
```
    Check whether the given exception is compatible with the specified exception types, as declared in a throws clause.
    
    Parameters:
    
    ex - the exception to check
    
    declaredExceptions - the exception types declared in the throws clause
    
    Returns:
    
    whether the given exception is compatible
  - isArray
```
public static boolean isArray(@Nullable
                              java.lang.Object obj)
```
    Determine whether the given object is an array: either an Object array or a primitive array.
    
    Parameters:
    
    obj - the object to check
  - isEmpty
```
public static boolean isEmpty(@Nullable
                              java.lang.Object[] array)
```
    Determine whether the given array is empty: i.e. null or of zero length.
    
    Parameters:
    
    array - the array to check
    
    See Also:
    
    isEmpty(Object)
  - isEmpty
```
public static boolean isEmpty(@Nullable
                              java.lang.Object obj)
```
    Determine whether the given object is empty.
    This method supports the following object types.
    - Optional: considered empty if Optional.empty()
    - Array: considered empty if its length is zero
    - CharSequence: considered empty if its length is zero
    - Collection: delegates to Collection.isEmpty()
    - Map: delegates to Map.isEmpty()
    If the given object is non-null and not one of the aforementioned supported types, this method returns false.
    Parameters:
    
    obj - the object to check
    
    Returns:
    
    true if the object is null or empty
    
    Since:
    
    4.2
    
    See Also:
    
    Optional.isPresent(), isEmpty(Object[]), StringUtils.hasLength(CharSequence), StringUtils.isEmpty(Object), CollectionUtils.isEmpty(java.util.Collection), CollectionUtils.isEmpty(java.util.Map)
  - unwrapOptional
```
@Nullable
public static java.lang.Object unwrapOptional(@Nullable
                                                        java.lang.Object obj)
```
    Unwrap the given object which is potentially a Optional.
    
    Parameters:
    
    obj - the candidate object
    
    Returns:
    
    either the value held within the Optional, null if the Optional is empty, or simply the given object as-is
    
    Since:
    
    5.0
  - containsElement
```
public static boolean containsElement(@Nullable
                                      java.lang.Object[] array,
                                      java.lang.Object element)
```
    Check whether the given array contains the given element.
    
    Parameters:
    
    array - the array to check (may be null, in which case the return value will always be false)
    
    element - the element to check for
    
    Returns:
    
    whether the element has been found in the given array
  - containsConstant
```
public static boolean containsConstant(java.lang.Enum<?>[] enumValues,
                                       java.lang.String constant)
```
    Check whether the given array of enum constants contains a constant with the given name, ignoring case when determining a match.
    
    Parameters:
    
    enumValues - the enum values to check, typically obtained via MyEnum.values()
    
    constant - the constant name to find (must not be null or empty string)
    
    Returns:
    
    whether the constant has been found in the given array
  - containsConstant
```
public static boolean containsConstant(java.lang.Enum<?>[] enumValues,
                                       java.lang.String constant,
                                       boolean caseSensitive)
```
    Check whether the given array of enum constants contains a constant with the given name.
    
    Parameters:
    
    enumValues - the enum values to check, typically obtained via MyEnum.values()
    
    constant - the constant name to find (must not be null or empty string)
    
    caseSensitive - whether case is significant in determining a match
    
    Returns:
    
    whether the constant has been found in the given array
  - caseInsensitiveValueOf
```
public static <E extends java.lang.Enum<?>> E caseInsensitiveValueOf(E[] enumValues,
                                                                     java.lang.String constant)
```
    Case insensitive alternative to Enum.valueOf(Class, String).
    
    Type Parameters:
    
    E - the concrete Enum type
    
    Parameters:
    
    enumValues - the array of all Enum constants in question, usually per Enum.values()
    
    constant - the constant to get the enum value of
    
    Throws:
    
    java.lang.IllegalArgumentException - if the given constant is not found in the given array of enum values. Use containsConstant(Enum[], String) as a guard to avoid this exception.
  - addObjectToArray
```
public static <A,O extends A> A[] addObjectToArray(@Nullable
                                                   A[] array,
                                                   @Nullable
                                                   O obj)
```
    Append the given object to the given array, returning a new array consisting of the input array contents plus the given object.
    
    Parameters:
    
    array - the array to append to (can be null)
    
    obj - the object to append
    
    Returns:
    
    the new array (of the same component type; never null)
  - toObjectArray
```
public static java.lang.Object[] toObjectArray(@Nullable
                                               java.lang.Object source)
```
    Convert the given array (which may be a primitive array) to an object array (if necessary of primitive wrapper objects).
    A null source value will be converted to an empty Object array.
    
    Parameters:
    
    source - the (potentially primitive) array
    
    Returns:
    
    the corresponding object array (never null)
    
    Throws:
    
    java.lang.IllegalArgumentException - if the parameter is not an array
  - nullSafeEquals
```
public static boolean nullSafeEquals(@Nullable
                                     java.lang.Object o1,
                                     @Nullable
                                     java.lang.Object o2)
```
    Determine if the given objects are equal, returning true if both are null or false if only one is null.
    Compares arrays with Arrays.equals, performing an equality check based on the array elements rather than the array reference.
    
    Parameters:
    
    o1 - first Object to compare
    
    o2 - second Object to compare
    
    Returns:
    
    whether the given objects are equal
    
    See Also:
    
    Object.equals(Object), Arrays.equals(long[], long[])
  - arrayEquals
```
private static boolean arrayEquals(java.lang.Object o1,
                                   java.lang.Object o2)
```
    Compare the given arrays with Arrays.equals, performing an equality check based on the array elements rather than the array reference.
    
    Parameters:
    
    o1 - first array to compare
    
    o2 - second array to compare
    
    Returns:
    
    whether the given objects are equal
    
    See Also:
    
    nullSafeEquals(Object, Object), Arrays.equals(long[], long[])
  - nullSafeHashCode
```
public static int nullSafeHashCode(@Nullable
                                   java.lang.Object obj)
```
    Return as hash code for the given object; typically the value of Object#hashCode()}. If the object is an array, this method will delegate to any of the nullSafeHashCode methods for arrays in this class. If the object is null, this method returns 0.
    
    See Also:
    
    Object.hashCode(), nullSafeHashCode(Object[]), nullSafeHashCode(boolean[]), nullSafeHashCode(byte[]), nullSafeHashCode(char[]), nullSafeHashCode(double[]), nullSafeHashCode(float[]), nullSafeHashCode(int[]), nullSafeHashCode(long[]), nullSafeHashCode(short[])
  - nullSafeHashCode
```
public static int nullSafeHashCode(@Nullable
                                   java.lang.Object[] array)
```
    Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
  - nullSafeHashCode
```
public static int nullSafeHashCode(@Nullable
                                   boolean[] array)
```
    Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
  - nullSafeHashCode
```
public static int nullSafeHashCode(@Nullable
                                   byte[] array)
```
    Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
  - nullSafeHashCode
```
public static int nullSafeHashCode(@Nullable
                                   char[] array)
```
    Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
  - nullSafeHashCode
```
public static int nullSafeHashCode(@Nullable
                                   double[] array)
```
    Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
  - nullSafeHashCode
```
public static int nullSafeHashCode(@Nullable
                                   float[] array)
```
    Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
  - nullSafeHashCode
```
public static int nullSafeHashCode(@Nullable
                                   int[] array)
```
    Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
  - nullSafeHashCode
```
public static int nullSafeHashCode(@Nullable
                                   long[] array)
```
    Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
  - nullSafeHashCode
```
public static int nullSafeHashCode(@Nullable
                                   short[] array)
```
    Return a hash code based on the contents of the specified array. If array is null, this method returns 0.
  - hashCode
```
@Deprecated
public static int hashCode(boolean bool)
```
    Deprecated. as of Spring Framework 5.0, in favor of the native JDK 8 variant
    
    Return the same value as Boolean.hashCode(boolean)}.
  - hashCode
```
@Deprecated
public static int hashCode(double dbl)
```
    Deprecated. as of Spring Framework 5.0, in favor of the native JDK 8 variant
    
    Return the same value as Double.hashCode(double)}.
  - hashCode
```
@Deprecated
public static int hashCode(float flt)
```
    Deprecated. as of Spring Framework 5.0, in favor of the native JDK 8 variant
    
    Return the same value as Float.hashCode(float)}.
  - hashCode
```
@Deprecated
public static int hashCode(long lng)
```
    Deprecated. as of Spring Framework 5.0, in favor of the native JDK 8 variant
    
    Return the same value as Long.hashCode(long)}.
  - identityToString
```
public static java.lang.String identityToString(@Nullable
                                                java.lang.Object obj)
```
    Return a String representation of an object's overall identity.
    
    Parameters:
    
    obj - the object (may be null)
    
    Returns:
    
    the object's identity as String representation, or an empty String if the object was null
  - getIdentityHexString
```
public static java.lang.String getIdentityHexString(java.lang.Object obj)
```
    Return a hex String form of an object's identity hash code.
    
    Parameters:
    
    obj - the object
    
    Returns:
    
    the object's identity code in hex notation
  - getDisplayString
```
public static java.lang.String getDisplayString(@Nullable
                                                java.lang.Object obj)
```
    Return a content-based String representation if obj is not null; otherwise returns an empty String.
    Differs from nullSafeToString(Object) in that it returns an empty String rather than "null" for a null value.
    
    Parameters:
    
    obj - the object to build a display String for
    
    Returns:
    
    a display String representation of obj
    
    See Also:
    
    nullSafeToString(Object)
  - nullSafeClassName
```
public static java.lang.String nullSafeClassName(@Nullable
                                                 java.lang.Object obj)
```
    Determine the class name for the given object.
    Returns a "null" String if obj is null.
    
    Parameters:
    
    obj - the object to introspect (may be null)
    
    Returns:
    
    the corresponding class name
  - nullSafeToString
```
public static java.lang.String nullSafeToString(@Nullable
                                                java.lang.Object obj)
```
    Return a String representation of the specified Object.
    Builds a String representation of the contents in case of an array. Returns a "null" String if obj is null.
    
    Parameters:
    
    obj - the object to build a String representation for
    
    Returns:
    
    a String representation of obj
  - nullSafeToString
```
public static java.lang.String nullSafeToString(@Nullable
                                                java.lang.Object[] array)
```
    Return a String representation of the contents of the specified array.
    The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.
    
    Parameters:
    
    array - the array to build a String representation for
    
    Returns:
    
    a String representation of array
  - nullSafeToString
```
public static java.lang.String nullSafeToString(@Nullable
                                                boolean[] array)
```
    Return a String representation of the contents of the specified array.
    The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.
    
    Parameters:
    
    array - the array to build a String representation for
    
    Returns:
    
    a String representation of array
  - nullSafeToString
```
public static java.lang.String nullSafeToString(@Nullable
                                                byte[] array)
```
    Return a String representation of the contents of the specified array.
    The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.
    
    Parameters:
    
    array - the array to build a String representation for
    
    Returns:
    
    a String representation of array
  - nullSafeToString
```
public static java.lang.String nullSafeToString(@Nullable
                                                char[] array)
```
    Return a String representation of the contents of the specified array.
    The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.
    
    Parameters:
    
    array - the array to build a String representation for
    
    Returns:
    
    a String representation of array
  - nullSafeToString
```
public static java.lang.String nullSafeToString(@Nullable
                                                double[] array)
```
    Return a String representation of the contents of the specified array.
    The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.
    
    Parameters:
    
    array - the array to build a String representation for
    
    Returns:
    
    a String representation of array
  - nullSafeToString
```
public static java.lang.String nullSafeToString(@Nullable
                                                float[] array)
```
    Return a String representation of the contents of the specified array.
    The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.
    
    Parameters:
    
    array - the array to build a String representation for
    
    Returns:
    
    a String representation of array
  - nullSafeToString
```
public static java.lang.String nullSafeToString(@Nullable
                                                int[] array)
```
    Return a String representation of the contents of the specified array.
    The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.
    
    Parameters:
    
    array - the array to build a String representation for
    
    Returns:
    
    a String representation of array
  - nullSafeToString
```
public static java.lang.String nullSafeToString(@Nullable
                                                long[] array)
```
    Return a String representation of the contents of the specified array.
    The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.
    
    Parameters:
    
    array - the array to build a String representation for
    
    Returns:
    
    a String representation of array
  - nullSafeToString
```
public static java.lang.String nullSafeToString(@Nullable
                                                short[] array)
```
    Return a String representation of the contents of the specified array.
    The String representation consists of a list of the array's elements, enclosed in curly braces ("{}"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Returns a "null" String if array is null.
    
    Parameters:
    
    array - the array to build a String representation for
    
    Returns:
    
    a String representation of array

Class ObjectUtils

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

INITIAL_HASH

MULTIPLIER

EMPTY_STRING

NULL_STRING

ARRAY_START

ARRAY_END

EMPTY_ARRAY

ARRAY_ELEMENT_SEPARATOR

Constructor Detail

ObjectUtils

Method Detail

isCheckedException

isCompatibleWithThrowsClause

isArray

isEmpty

isEmpty

unwrapOptional

containsElement

containsConstant

containsConstant

caseInsensitiveValueOf

addObjectToArray

toObjectArray

nullSafeEquals

arrayEquals

nullSafeHashCode

nullSafeHashCode

nullSafeHashCode

nullSafeHashCode

nullSafeHashCode

nullSafeHashCode

nullSafeHashCode

nullSafeHashCode

nullSafeHashCode

nullSafeHashCode

hashCode

hashCode

hashCode

hashCode

identityToString

getIdentityHexString

getDisplayString

nullSafeClassName

nullSafeToString

nullSafeToString

nullSafeToString

nullSafeToString

nullSafeToString

nullSafeToString

nullSafeToString

nullSafeToString

nullSafeToString

nullSafeToString