ObjectsCompat

public static boolean equals(@Nullable Object a, @Nullable Object b)

Returns true if the arguments are equal to each other and false otherwise.

Consequently, if both arguments are null, true is returned and if exactly one argument is null, false is returned. Otherwise, equality is determined by using the equals method of the first argument.

public static int hash(@Nullable Object[] values)

Generates a hash code for a sequence of input values. The hash code is generated as if all the input values were placed into an array, and that array were hashed by calling hashCode.

This method is useful for implementing hashCode on objects containing multiple fields. For example, if an object that has three fields, x, y, and z, one could write:

@Override public int hashCode() {
    return ObjectsCompat.hash(x, y, z);
}

public static int hashCode(@Nullable Object o)

Returns the hash code of a non-null argument and 0 for a null argument.

public static @NonNull T <T> requireNonNull(@Nullable T obj)

Checks that the specified object reference is not null. This method is designed primarily for doing parameter validation in methods and constructors, as demonstrated below:

public Foo(Bar bar) {
    this.bar = Objects.requireNonNull(bar);
}

public static @NonNull T <T> requireNonNull(@Nullable T obj, @NonNull String message)

Checks that the specified object reference is not null and throws a customized NullPointerException if it is. This method is designed primarily for doing parameter validation in methods and constructors with multiple parameters, as demonstrated below:

public Foo(Bar bar, Baz baz) {
    this.bar = Objects.requireNonNull(bar, "bar must not be null");
    this.baz = Objects.requireNonNull(baz, "baz must not be null");
}

public static @Nullable String toString(@Nullable Object o, @Nullable String nullDefault)

Returns the result of calling toString on the first argument if the first argument is not null and returns the second argument otherwise.