Get Null-safe Map values in Java

Purpose of this article

It is a Null Pointer Exception that comes with Java, but I wanted to get the value as safely as possible, so this time I tried the method of getting the value of Map.

Map to be verified

Map<String, Boolean> map = new HashMap<String, Boolean>() {
    put("true_label", true);
    put("false_label", false);
    put("null_label", null);

Map # get normally


assertNull(map.get("invalid_label")); //Keys that do not exist in Map

Java 8 Map # getOrDefault

You can get an alternative value if you don't have the key.

assertTrue(map.getOrDefault("true_label", false));
assertFalse(map.getOrDefault("false_label", false));
assertFalse(map.getOrDefault("invalid_label", false)); //You can get an alternative value if you don't have the key.

assertNull(map.getOrDefault("null_label", false)); //Unfortunately it doesn't become false!!

Java 8 Optional # ofNullable

assertFalse(Optional.ofNullable(map.get("null_label")).orElse(false)); //Alternate value false
assertFalse(Optional.ofNullable(map.get("invalid_label")).orElse(false)); //Alternate value false

ObjectUtils # defaultIfNull in Apache.commons.lang3

Optional may be fine, but just in case

assertTrue(ObjectUtils.defaultIfNull(map.get("true_label"), false));
assertFalse(ObjectUtils.defaultIfNull(map.get("false_label"), false));
assertFalse(ObjectUtils.defaultIfNull(map.get("null_label"), false)); //Alternate value false
assertFalse(ObjectUtils.defaultIfNull(map.get("invalid_label"), false)); //Alternate value false

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