Field setFloat() method in Java with Examples

setFloat() method of java.lang.reflect.Field used to set the value of a field as a float on the specified object. When you need to set the value of a field of an object as a float then you can use this method to set value over an Object. Syntax:

public void setFloat(Object obj, float f)
            throws IllegalArgumentException,
                   IllegalAccessException

Parameters: This method accepts  two parameters:

• obj: which is the object whose field should be modified and
• f: 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 implementer 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 setFloat() method: Program 1:

Java

// Java program to illustrate setFloat() method

import 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 setFloat is "
            + emp.salary);

        // Get the marks field object
        Field field = Employee.class.getField("salary");

        // Apply setFloat Method
        field.setFloat(emp, 259939.99f);

        // print value of salary
        System.out.println(
            "Value of salary after "
            + "applying setFloat is "
            + emp.salary);

        // print value of pf
        System.out.println(
            "Value of pf before "
            + "applying setFloat is "
            + emp.pf);

        // Get the marks field object
        field = Employee.class.getField("pf");

        // Apply setFloat Method
        field.setFloat(emp, 234234.34f);

        // print value of pf
        System.out.println(
            "Value of pf after "
            + "applying setFloat is "
            + emp.pf);
    }
}

// sample class
class Employee {

    // static float values
    public static float pf = 122342.89f;
    public static float salary = 143125f;
}

Output:

Value of salary before applying setFloat is 143125.0
Value of salary after applying setFloat is 259939.98
Value of pf before applying setFloat is 122342.89
Value of pf after applying setFloat is 234234.34

Program 2:

Java

// Java program to illustrate setFloat() 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 setFloat Method
        field.setFloat(no, 3244.466f);

        // print value of isActive
        System.out.println(
            "Value after "
            + "applying setFloat is "
            + Numbers.value);
    }
}

// sample Numbers class
class Numbers {

    // static float value
    public static float value = 26774.3685f;
}

Output:

Value after applying setFloat is 3244.466

Reference: https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Field.html#setFloat-java.lang.Object-float-