JAVA-E1054 · Boxed Boolean values should not be used in conditional expressions

Boxed Boolean values should not be used in conditional expressions JAVA-E1054

Bug risk

Major

2 years ago — 2 years old

This would throw a NullPointerException if value were null

src/main/java/net/shadew/json/JsonNode.java

 120     */
 121    static JsonNode bool(Boolean value) {
 122        if (value == null) return NULL;
 123        return value ? TRUE : FALSE; 124    }
 125
 126    /**

This would throw a NullPointerException if t1 were null

plugins_src/tic_tac_toe_plugin/src/main/java/gq/glowman554/bot/ttt/TicTacToeAi.java

 50
 51	private int minmax(TicTacToeField player, int depth, boolean is_maximizing) {
 52		Pair<Boolean, TicTacToeField> game_over = is_game_over();
 53		if (game_over.t1) { 54			if (game_over.t2 == TicTacToeField.FIELD_X) {
 55				return -10 + depth;
 56			} else if (game_over.t2 == TicTacToeField.FIELD_O) {

This would throw a NullPointerException if t1 were null

plugins_src/tic_tac_toe_plugin/src/main/java/gq/glowman554/bot/ttt/TicTacToeAi.java

 50
 51	private int minmax(TicTacToeField player, int depth, boolean is_maximizing) {
 52		Pair<Boolean, TicTacToeField> game_over = is_game_over();
 53		if (game_over.t1) { 54			if (game_over.t2 == TicTacToeField.FIELD_X) {
 55				return -10 + depth;
 56			} else if (game_over.t2 == TicTacToeField.FIELD_O) {

This would throw a NullPointerException if t1 were null

plugins_src/tic_tac_toe_plugin/src/main/java/gq/glowman554/bot/TicTacToePlugin.java

42
43					event.commandEvent.message_quote(parser.toString());
44
45					if (ai.is_game_over().t1) {46						if (ai.is_game_over().t2 == TicTacToeField.FIELD_X) {
47							event.commandEvent.message_quote("You won! How???");
48						} else {

This would throw a NullPointerException if t1 were null

plugins_src/tic_tac_toe_plugin/src/main/java/gq/glowman554/bot/TicTacToePlugin.java

42
43					event.commandEvent.message_quote(parser.toString());
44
45					if (ai.is_game_over().t1) {46						if (ai.is_game_over().t2 == TicTacToeField.FIELD_X) {
47							event.commandEvent.message_quote("You won! How???");
48						} else {

Description

A boxed boolean value (java.lang.Boolean) is being used in a potentially dangerous manner. Such usage may lead to a NullPointerException being thrown.

Java's primitive types differ from normal classes in that primitives can never be null. However, classes can be null, even primitive wrapper classes such as Boolean or Character. For Boolean in particular, this means that turning a boolean into a Boolean promotes it from a binary true or false to a ternary true, false or null. This may be undesirable in most cases, and is worth avoiding.

The nullability of wrapper types becomes an issue when the wrapper types are used directly in expressions without null checks.

Bad Practice

In the example below, the if statement evaluates the value of nullable when its value is null. This will lead to a NullPointerException being thrown.

Boolean nullable = null

if (nullable) { // This would throw a NullPointerException.
    // ...
}

Glowman554 / BetterNudel

Bad Practice

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