IntStream allMatch() in Java with examples

IntStream allMatch(IntPredicate predicate) returns whether all elements of this stream match the provided predicate. It may not evaluate the predicate on all elements if not necessary for determining the result. This is a short-circuiting terminal operation. A terminal operation is short-circuiting if, when presented with infinite input, it may terminate in finite time.
Syntax :

boolean allMatch(IntPredicate predicate)

Where, IntPredicate represents a predicate (boolean-valued function)
of one int-valued argument and the function returns true if either
all elements of the stream match the provided predicate or 
the stream is empty, otherwise false.

Note : If the stream is empty then true is returned and the predicate is not evaluated.

Example 1 : allMatch() function to check whether all elements are divisible by 3.

// Java code for IntStream allMatch
// (Predicate predicate) to check whether
// all elements of this stream match
// the provided predicate.
import java.util.*;
import java.util.stream.IntStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {

        // Creating an IntStream
        IntStream stream = IntStream.of(3, 5, 9, 12, 14);

        // Check if all elements of stream
        // are divisible by 3 or not using
        // IntStream allMatch(Predicate predicate)
        boolean answer = stream.allMatch(num -> num % 3 == 0);

        // Displaying the result
        System.out.println(answer);
    }
}

Output :

false

Example 2 : allMatch() function to check whether all elements in the IntStream obtained after concatenating two IntStreams are less than 2.

// Java code for IntStream allMatch
// (Predicate predicate) to check whether
// all elements of this stream match
// the provided predicate.
import java.util.*;
import java.util.stream.IntStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {

        // Creating an IntStream after concatenating
        // two IntStreams
        IntStream stream = IntStream.concat(IntStream.of(-2, -4, -6, -8),
                                            IntStream.of(-1, 0, 1, 5));

        // Check if all elements of stream
        // are less than 2 or not using
        // IntStream allMatch(Predicate predicate)
        boolean answer = stream.allMatch(num -> num < 2);

        // Displaying the result
        System.out.println(answer);
    }
}

Output :

false

Example 3 : allMatch() function to show if the stream is empty then true is returned.

// Java code for IntStream allMatch
// (Predicate predicate) to check whether
// any element of this stream match
// the provided predicate.
import java.util.*;
import java.util.stream.IntStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {

        // Creating an empty IntStream
        IntStream stream = IntStream.empty();

        boolean answer = stream.allMatch(num -> true);

        // Displaying the result
        System.out.println(answer);
    }
}

Output :

true