Field setInt() method in Java with Examples

02 Jun, 2022
setInt() method of java.lang.reflect.Field used to set the value of a field as an int on the specified object. When you need to set the value of a field of an object as int then you can use this method to set value over an Object. Syntax:
public void setInt(Object obj, int i)
            throws IllegalArgumentException,
                   IllegalAccessException
Parameters: This method accepts  two parameters:
obj: which is the object whose field should be modified and
i: which is the new value for the field of obj being modified.
Return: This method returns nothing. Exception: This method throws the following Exception:
IllegalAccessException: if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.
IllegalArgumentException: if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.
NullPointerException: if the specified object is null and the field is an instance field.
ExceptionInInitializerError: if the initialization provoked by this method fails.
Below programs illustrate setInt() method: Program 1: 
Java
// Java program to illustrate setInt() methodimport java.lang.reflect.Field; public class GFG {     public static void main(String[] args)        throws Exception    {         // create user object        Employee emp = new Employee();         // print value of salary        System.out.println(            "Value of salary before "            + "applying setInt is "            + emp.salary);         // Get the  field object        Field field = Employee.class.getField("salary");         // Apply setInt Method        field.setInt(emp, 2243599);         // print value of salary        System.out.println(            "Value of salary after "            + "applying setInt is "            + emp.salary);         // print value of uniqueNo        System.out.println(            "Value of uniqueNo before "            + "applying setInt is "            + emp.uniqueNo);         // Get the field object        field = Employee.class.getField("uniqueNo");         // Apply setInt Method        field.setInt(emp, 123434);         // print value of uniqueNo        System.out.println(            "Value of uniqueNo after "            + "applying setInt is "            + emp.uniqueNo);    }} // sample classclass Employee {     // static int values    public static int uniqueNo = 234289;    public static int salary = 1125213;}
Value of salary before applying setInt is 1125213
Value of salary after applying setInt is 2243599
Value of uniqueNo before applying setInt is 234289
Value of uniqueNo after applying setInt is 123434
Program 2: 
Java
// Java program to illustrate setInt() method import java.lang.reflect.Field; public class GFG {     public static void main(String[] args)        throws Exception    {         // create Numbers object        Numbers no = new Numbers();         // Get the value field object        Field field = Numbers.class                          .getField("value");         // Apply setInt Method        field.setInt(no, 53266);         // print value of isActive        System.out.println(            "Value after "            + "applying setInt is "            + Numbers.value);    }} // sample Numbers classclass Numbers {     // static int value    public static int value = 13685;}
Value after applying setInt is 53266
Reference: https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Field.html#setInt-java.lang.Object-int-
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