| java.lang.Object
 java.lang.Class
| Class | | final public class Class (Code) | | Instances of the class Class represent classes and interfaces
in a running Java application. Every array also belongs to a class that is
reflected as a Class object that is shared by all arrays with
the same element type and number of dimensions.
Class has no public constructor. Instead Class
objects are constructed automatically by the Java Virtual Machine as classes
are loaded.
The following example uses a Class object to print the
class name of an object:
void printClassName(Object obj) {
System.out.println("The class of " + obj +
" is " + obj.getClass().getName());
}
version:
12/17/01 (CLDC 1.1)
since:
JDK1.0, CLDC 1.0 |
| Method Summary | |
| native public static Class | forName(String className)
Returns the Class object associated with the class
with the given string name. | | native public 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.
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. | | public java.io.InputStream | getResourceAsStream(String name)
Finds a resource with a given name in the application's
JAR file. | | void | initialize()
| | native public boolean | isArray()
Determines if this Class object represents an array class. | | native public 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. | | native public boolean | isInstance(Object obj)
Determines if the specified Object is assignment-compatible
with the object represented by this Class. | | native public boolean | isInterface()
Determines if the specified Class object represents an
interface type. | | native public Object | newInstance()
Creates a new instance of a class.
a newly allocated instance of the class represented by thisobject. | | public String | toString()
Converts the object to a string. |
| forName | | native public static Class forName(String className) throws ClassNotFoundException(Code) | | Returns the 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")
Parameters:
className - the fully qualified name of the desired class. the Class object for the class with thespecified name.
exception:
ClassNotFoundException - if the class could not be found.
exception:
Error - if the function fails for any other reason.
since:
JDK1.0 |
| getName | | native public String getName()(Code) | | Returns the fully-qualified name of the entity (class, interface, array
class, primitive type, or void) represented by this 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:
(new Object[3]).getClass().getName()
returns "[Ljava.lang.Object;" and:
(new int[3][4][5][6][7][8][9]).getClass().getName()
returns "[[[[[[[I". The encoding of element type names
is as follows:
B byte
C char
D double
F float
I int
J long
Lclassname; class or interface
S short
Z boolean
The class or interface name classname is given in fully
qualified form as shown in the example above.
the fully qualified name of the class or interfacerepresented by this object. |
| getResourceAsStream | | public java.io.InputStream getResourceAsStream(String name)(Code) | | Finds a resource with a given name in the application's
JAR file. This method returns
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:
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.
Parameters:
name - name of the desired resource a java.io.InputStream object. |
| isArray | | native public boolean isArray()(Code) | | Determines if this Class object represents an array class.
true if this object represents an array class;false otherwise.
since:
JDK1.1 |
| isAssignableFrom | | native public boolean isAssignableFrom(Class cls)(Code) | | 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. 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.
Parameters:
cls - the Class object to be checked the boolean value indicating whether objects of thetype cls can be assigned to objects of this class
exception:
NullPointerException - if the specified Class parameter isnull.
since:
JDK1.1 |
| isInstance | | native public boolean isInstance(Object obj)(Code) | | Determines if the specified 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.
Parameters:
obj - the object to check true if obj is an instance of this class
since:
JDK1.1 |
| isInterface | | native public boolean isInterface()(Code) | | Determines if the specified Class object represents an
interface type.
true if this object represents an interface;false otherwise. |
| newInstance | | native public Object newInstance() throws InstantiationException, IllegalAccessException(Code) | | Creates a new instance of a class.
a newly allocated instance of the class represented by thisobject. This is done exactly as if by a newexpression with an empty argument list.
exception:
IllegalAccessException - if the class or initializer isnot accessible.
exception:
InstantiationException - if an application tries toinstantiate an abstract class or an interface, or if theinstantiation fails for some other reason.
since:
JDK1.0 |
| toString | | public String toString()(Code) | | Converts the object to a string. The string representation is the
string "class" or "interface", followed by a space, and then by the
fully qualified name of the class in the format returned by
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".
a string representation of this class object. |
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