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Java Utils - Objects.requireNonNull() Examples

Java Utils Java Java API 

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Class:

java.util.Objects

java.lang.Objectjava.lang.Objectjava.util.Objectsjava.util.ObjectsLogicBig

Methods:

These methods check that the specified object reference is not null. They are useful for parameter validation in methods and constructors. 

public static <T> T requireNonNull(T obj)

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

public static <T> T requireNonNull(T obj, Supplier<String> messageSupplier)

Examples


package com.logicbig.example.objects;

import java.util.Objects;

public class RequireNonNullExample {

    public static void main(String... args) {
        String str = null;
        str = Objects.requireNonNull(str);
    }
}

Output

Caused by: java.lang.NullPointerException
	at java.util.Objects.requireNonNull(Objects.java:203)
	at com.logicbig.example.objects.RequireNonNullExample.main(RequireNonNullExample.java:14)
	... 6 more




package com.logicbig.example.objects;

import java.util.Objects;

public class RequireNonNullExample2 {

    public static void main(String... args) {
        String str = null;
        str = Objects.requireNonNull(str, "str cannot be null");
    }
}

Output

Caused by: java.lang.NullPointerException: str cannot be null
	at java.util.Objects.requireNonNull(Objects.java:228)
	at com.logicbig.example.objects.RequireNonNullExample2.main(RequireNonNullExample2.java:14)
	... 6 more




package com.logicbig.example.objects;

import java.util.Objects;

public class RequireNonNullExample3 {

    public static void main(String... args) {
        String str = null;
        //useful when creating the message is expensive
        Objects.requireNonNull(str, RequireNonNullExample3::createMessage);
    }

    private static String createMessage() {
        return "a demo string";
    }
}

Output

Caused by: java.lang.NullPointerException: a demo string
	at java.util.Objects.requireNonNull(Objects.java:290)
	at com.logicbig.example.objects.RequireNonNullExample3.main(RequireNonNullExample3.java:15)
	... 6 more

See Also