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java.lang.Objectjava.lang.Class<T>
public class Class<T>
Method Summary | |
---|---|
static Class<?> |
forName(String aName)
Returns the Class object associated with the class
with the given string name. |
String |
getName()
Returns the fully-qualified name of the entity (class, interface, array class, primitive type, or void) represented by this Class
object, as a String . |
InputStream |
getResourceAsStream(String resource)
Finds a resource with a given name in the application's JAR file. |
Class<? super T> |
getSuperclass()
|
boolean |
isArray()
Determines if this Class object represents an array class. |
boolean |
isAssignableFrom(Class<?> cls)
Determines if the class or interface represented by this Class object is either the same as, or is a superclass or
superinterface of, the class or interface represented by the specified
Class parameter. |
boolean |
isInstance(Object o)
Determines if the specified Object is assignment-compatible
with the object represented by this Class . |
boolean |
isInterface()
Determines if the specified Class object represents an
interface type. |
boolean |
isPrimitive()
|
Object |
newInstance()
Creates a new instance of a class. |
String |
toString()
Converts the object to a string. |
Methods inherited from class java.lang.Object |
---|
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Method Detail |
---|
public String toString()
getName
. If this Class
object represents a
primitive type, this method returns the name of the primitive type. If
this Class
object represents void this method returns
"void".
toString
in class Object
public static Class<?> forName(String aName) throws ClassNotFoundException
Class
object associated with the class
with the given string name. Given the fully-qualified name for
a class or interface, this method attempts to locate, load and
link the class.
For example, the following code fragment returns the runtime
Class
descriptor for the class named
java.lang.Thread
:
Class t = Class.forName("java.lang.Thread")
aName
- the fully qualified name of the desired class.
Class
object for the class with the
specified name.
ClassNotFoundException
- if the class could not be found.
Error
- if the function fails for any other reason.public boolean isInstance(Object o)
Object
is assignment-compatible
with the object represented by this Class
. This method is
the dynamic equivalent of the Java language instanceof
operator. The method returns true
if the specified
Object
argument is non-null and can be cast to the
reference type represented by this Class
object without
raising a ClassCastException.
It returns false
otherwise.
Specifically, if this Class
object represents a
declared class, this method returns true
if the specified
Object
argument is an instance of the represented class (or
of any of its subclasses); it returns false
otherwise. If
this Class
object represents an array class, this method
returns true
if the specified Object
argument
can be converted to an object of the array class by an identity
conversion or by a widening reference conversion; it returns
false
otherwise. If this Class
object
represents an interface, this method returns true
if the
class or any superclass of the specified Object
argument
implements this interface; it returns false
otherwise. If
this Class
object represents a primitive type, this method
returns false
.
o
- the object to check
obj
is an instance of this classpublic boolean isAssignableFrom(Class<?> cls)
Class
object is either the same as, or is a superclass or
superinterface of, the class or interface represented by the specified
Class
parameter. It returns true
if so;
otherwise it returns false
. If this Class
object represents a primitive type, this method returns
true
if the specified Class
parameter is
exactly this Class
object; otherwise it returns
false
.
Specifically, this method tests whether the type represented by the
specified Class
parameter can be converted to the type
represented by this Class
object via an identity conversion
or via a widening reference conversion. See The Java Language
Specification, sections 5.1.1 and 5.1.4 , for details.
cls
- the Class
object to be checked
boolean
value indicating whether objects of the
type cls
can be assigned to objects of this class
NullPointerException
- if the specified Class parameter is
null.public boolean isInterface()
Class
object represents an
interface type.
true
if this object represents an interface;
false
otherwise.public boolean isArray()
Class
object represents an array class.
true
if this object represents an array class;
false
otherwise.public boolean isPrimitive()
public Class<? super T> getSuperclass()
public InputStream getResourceAsStream(String resource)
null
if no resource with this name is found
in the application's JAR file.
The resource names can be represented in two different formats: absolute or relative.
Absolute format:
/packagePathName/resourceName
Relative format:
resourceName
In the absolute format, the programmer provides a fully qualified name that includes both the full path and the name of the resource inside the JAR file. In the path names, the character "/" is used as the separator.
In the relative format, the programmer provides only
the name of the actual resource. Relative names are
converted to absolute names by the system by prepending
the resource name with the fully qualified package name
of class upon which the getResourceAsStream
method was called.
resource
- name of the desired resource
java.io.InputStream
object.public String getName()
Class
object, as a String
.
If this Class
object represents a class of arrays, then
the internal form of the name consists of the name of the element type
in Java signature format, preceded by one or more "["
characters representing the depth of array nesting. Thus:
returns "(new Object[3]).getClass().getName()
[Ljava.lang.Object;
" and:
returns "(new int[3][4][5][6][7][8][9]).getClass().getName()
[[[[[[[I
". The encoding of element type names
is as follows:
The class or interface name classname is given in fully qualified form as shown in the example above.B byte C char D double F float I int J long Lclassname; class or interface S short Z boolean
public Object newInstance() throws InstantiationException, IllegalAccessException
new
expression with an empty argument list.
IllegalAccessException
- if the class or initializer is
not accessible.
InstantiationException
- if an application tries to
instantiate an abstract class or an interface, or if the
instantiation fails for some other reason.
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