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Summary: Nested | Field | Method | Constr | Detail: Nested | Field | Method | Constr |
java.lang.Object
java.nio.charset.Charset
Method Summary | |
static SortedMap | |
Set |
|
boolean | |
int | |
abstract boolean | |
CharBuffer |
|
static Charset |
|
String | |
String |
|
ByteBuffer | |
ByteBuffer |
|
boolean | |
static Charset | |
int |
|
boolean | |
static boolean |
|
String |
|
abstract CharsetDecoder | |
abstract CharsetEncoder | |
String |
|
Methods inherited from class java.lang.Object | |
clone , equals , extends Object> getClass , finalize , hashCode , notify , notifyAll , toString , wait , wait , wait |
public static Charset defaultCharset()
Returns the system default charset. This may be set by the user or VM with the file.encoding property.
- Since:
- 1.5
public final boolean equals(Object ob)
Determine whether this Object is semantically equal to another Object.There are some fairly strict requirements on this method which subclasses must follow:
- It must be transitive. If
a.equals(b)
andb.equals(c)
, thena.equals(c)
must be true as well.- It must be symmetric.
a.equals(b)
andb.equals(a)
must have the same value.- It must be reflexive.
a.equals(a)
must always be true.- It must be consistent. Whichever value a.equals(b) returns on the first invocation must be the value returned on all later invocations.
a.equals(null)
must be false.- It must be consistent with hashCode(). That is,
a.equals(b)
must implya.hashCode() == b.hashCode()
. The reverse is not true; two objects that are not equal may have the same hashcode, but that has the potential to harm hashing performance.This is typically overridden to throw a
ClassCastException
if the argument is not comparable to the class performing the comparison, but that is not a requirement. It is legal fora.equals(b)
to be true even thougha.getClass() != b.getClass()
. Also, it is typical to never cause aNullPointerException
.In general, the Collections API (
java.util
) use theequals
method rather than the==
operator to compare objects. However,IdentityHashMap
is an exception to this rule, for its own good reasons.The default implementation returns
this == o
.
- Parameters:
- Returns:
- whether this Object is semantically equal to another
- See Also:
Object.hashCode()
public static Charset forName(String charsetName)
Returns the Charset instance for the charset of the given name.
- Parameters:
charsetName
-
- Returns:
- the Charset instance for the indicated charset
- Throws:
UnsupportedCharsetException
- if this VM does not support the charset of the given name.IllegalCharsetNameException
- if the given charset name is legal.IllegalArgumentException
- ifcharsetName
is null.
public final int hashCode()
Get a value that represents this Object, as uniquely as possible within the confines of an int.There are some requirements on this method which subclasses must follow:
- Semantic equality implies identical hashcodes. In other words, if
a.equals(b)
is true, thena.hashCode() == b.hashCode()
must be as well. However, the reverse is not necessarily true, and two objects may have the same hashcode without being equal.- It must be consistent. Whichever value o.hashCode() returns on the first invocation must be the value returned on all later invocations as long as the object exists. Notice, however, that the result of hashCode may change between separate executions of a Virtual Machine, because it is not invoked on the same object.
Notice that since
hashCode
is used inHashtable
and other hashing classes, a poor implementation will degrade the performance of hashing (so don't blindly implement it as returning a constant!). Also, if calculating the hash is time-consuming, a class may consider caching the results.The default implementation returns
System.identityHashCode(this)
- Returns:
- the hash code for this Object
public final String toString()
Convert this Object to a human-readable String. There are no limits placed on how long this String should be or what it should contain. We suggest you make it as intuitive as possible to be able to place it intoSystem.out.println()
and such.It is typical, but not required, to ensure that this method never completes abruptly with a
RuntimeException
.This method will be called when performing string concatenation with this object. If the result is
null
, string concatenation will instead use"null"
.The default implementation returns
getClass().getName() + "@" + Integer.toHexString(hashCode())
.
- Returns:
- the String representing this Object, which may be null
- See Also:
getClass()
,Object.hashCode()
,Class.getName()
,Integer.toHexString(int)