The hashCode() method of java.lang.reflect.Field used to get the hashcode for this Field. Final Hashcode is computed as the exclusive-or of the hashcodes for the underlying field’s declaring class name and its name. The hashcode is always the same if the object doesn’t change. Hashcode is a unique code generated by the JVM at the time of object creation. It can be used to perform some operation on hashing related algorithm like a hashtable, hashmap etc. An object can also be searched with this unique code.
Syntax:
public int hashCode()
Parameters: This method accepts nothing.
Return value: This method returns an integer which is the hash code value for this object.
Below programs illustrate hashCode() method:
Program 1:
// Java program to demonstrate hashCode() method import java.lang.reflect.Field; public class GFG { public static void main(String[] args) throws Exception { // Get the marks field object Field field = User.class.getField("Marks"); // Apply hashCode Method on User Object // to get the hashCode of Marks field int value = field.hashCode(); // print result System.out.println("HashCode of Marks field" + " is " + value); // Now Get the Fees field object field = User.class.getField("Fees"); // Apply hashCode Method on User Object // to get the hashcode of Fees field value = field.hashCode(); // print result System.out.println("HashCode of Fees field" + " is " + value); // Now Get the name field object field = User.class.getField("name"); // Apply hashCode Method on User Object // to get the hashCode of name field value = field.hashCode(); // print result System.out.println("HashCode of name field" + " is " + value); }} // sample User classclass User { // static double values public static double Marks = 34.13; public static float Fees = 3413.99f; public static String name = "Aman"; public static double getMarks() { return Marks; } public static void setMarks(double marks) { Marks = marks; } public static float getFees() { return Fees; } public static void setFees(float fees) { Fees = fees; } public static String getName() { return name; } public static void setName(String name) { User.name = name; }} |
HashCode of Marks field is 71482573 HashCode of Fees field is 591398 HashCode of name field is 1779040
Program 2:
// Java program to demonstrate hashCode() method import java.lang.reflect.Field;import java.time.Month; public class GFG { public static void main(String[] args) throws Exception { // Get all field objects of Month class Field[] fields = Month.class.getFields(); for (int i = 0; i < fields.length; i++) { // print name of Fields System.out.println("HashCode of Field: " + fields[i].hashCode()); } }} |
HashCode of Field: -297508095 HashCode of Field: 1296412905 HashCode of Field: 1475695976 HashCode of Field: 1343692077 HashCode of Field: 1404020238 HashCode of Field: 1401709321 HashCode of Field: 1401709395 HashCode of Field: 538235208 HashCode of Field: 2125827066 HashCode of Field: -1718938229 HashCode of Field: -1007182215 HashCode of Field: 59532142
References: https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Field.html#hashCode–
