Method Class | getParameterCount() method in Java
The java.lang.reflect.Method.getParameterCount() method of Method class returns the number of parameters declared on a method Object.
Syntax:
public int getParameterCount()
Return Value: This method returns number of formal parameters defined on this Method Object.
Below programs illustrates getParameterCount() method of Method class:
Example 1: Below Program returns No of Parameter for a specific Method given as Input.
import java.lang.reflect.Method;
public class GFG {
public static void main(String[] args)
{
try {
Class classobj = GFG. class ;
Method[] methods = classobj.getMethods();
int noOfParameters = methods[ 0 ].getParameterCount();
System.out.println( "Method Name: "
+ methods[ 0 ].getName());
System.out.println( "No of parameters:" + noOfParameters);
}
catch (Exception e) {
e.printStackTrace();
}
}
public void setManyValues(String parameter1)
{
System.out.println( "setManyValues" );
}
}
|
Output:
Method Name: setManyValues
No of parameters:1
Example 2: Below Program return No of Parameters for all of Methods Defined in a class.
import java.lang.reflect.Method;
public class GFG {
public static void main(String[] args)
{
try {
Class classobj = DemoClass. class ;
Method[] methods = classobj.getMethods();
for (Method method : methods) {
System.out.print( "Method Name is "
+ method.getName());
int noOfParameters = method.getParameterCount();
System.out.println( " and No of parameters = "
+ noOfParameters);
}
}
catch (Exception e) {
e.printStackTrace();
}
}
}
class DemoClass {
public void DemoMethod1(String parameter1)
{
System.out.println( "DemoMethod1" );
}
public void DemoMethod2(String parameter1,
String parameter2)
{
System.out.println( "DemoMethod2" );
}
public void DemoMethod3()
{
System.out.println( "DemoMethod3" );
}
}
|
Output:
Method Name is DemoMethod1 and No of parameters = 1
Method Name is DemoMethod2 and No of parameters = 2
Method Name is DemoMethod3 and No of parameters = 0
Method Name is wait and No of parameters = 2
Method Name is wait and No of parameters = 1
Method Name is wait and No of parameters = 0
Method Name is equals and No of parameters = 1
Method Name is toString and No of parameters = 0
Method Name is hashCode and No of parameters = 0
Method Name is getClass and No of parameters = 0
Method Name is notify and No of parameters = 0
Method Name is notifyAll and No of parameters = 0
Explanation: Output of this program also showing results for method objects other than methods defined in class object like wait, equals, toString, hashCode, getClass, notify, notifyAll. These methods are inherited from superclass name Object of java.lang lang package by class object.
Reference: https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Method.html#getParameterCount–
Last Updated :
05 Dec, 2018
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