Function overloading and constructor overloading in Java are techniques that allow multiple methods or constructors to have the same name but different parameters.

Function Overloading:
Function overloading occurs when multiple methods in the same class have the same name but differ in the number or type of their parameters. It allows a class to perform different tasks with the same method name, enhancing readability and usability. For instance, a class might have a method named `add` that adds two integers, another that adds two floats, and a third that concatenates two strings:

“`java
public class Calculator {
public int add(int a, int b) {
return a + b;
}

public double add(double a, double b) {
return a + b;
}

public String add(String a, String b) {
return a + b;
}
}
“`

Constructor Overloading:
Constructor overloading is similar but applies to constructors. A class can have multiple constructors, each with a different parameter list. This allows objects of the class to be instantiated in different ways, providing flexibility in object creation. For example, a `Person` class might have multiple constructors:

“`java
public class Person {
private String name;
private int age;

public Person() {
this.name = “Unknown”;
this.age = 0;
}

public Person(String name) {
this.name = name;
this.age = 0;
}

public Person(String name, int age) {
this.name = name;
this.age = age;
}
}
“`

In summary, function overloading and constructor overloading in Java enable multiple methods or constructors with the same name but different parameters, enhancing code flexibility and readability.