public class hashmapcheck {
public static void main(String args[]) {
    Person abhishek = new Person("abhishek");
    Map<Person,String> mapCheck = new HashMap<Person,String>();
    mapCheck.put(abhishek,"ancd");
    abhishek.setName("defg");
    System.out.println(mapCheck.get(abhishek));  //line which i try to undertand
}

public class Person {
public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

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

String name;

@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    Person person = (Person) o;

    return name != null ? name.equals(person.name) : person.name == null;
}

@Override
public int hashCode() {
    return name != null ? name.hashCode() : 0;
}