What methods does the Object class contain?

In Java, the Object class is the root class for all classes. It contains several key methods that are inherited by all objects:

• equals(Object obj) — compares the current object with another for equality.
• hashCode() — returns the hash code of the object, used in collections.
• toString() — returns a string representation of the object.
• getClass() — returns the Class object describing the class of the object.
• clone() — creates a copy of the object (requires implementation of the Cloneable interface).
• finalize() — called before garbage collection (deprecated method).
• wait(), notify(), notifyAll() — methods for thread work and synchronization.

Example of overriding the equals and hashCode methods:

@Override
public boolean equals(Object obj) {
    if (this == obj) return true;
    if (obj == null || getClass() != obj.getClass()) return false;
    MyClass other = (MyClass) obj;
    return this.id == other.id;
}

@Override
public int hashCode() {
    return Objects.hash(id);
}