The literals should be first in String comparisons
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ID: java-best-practices/literals-first-in-comparison
Language: Java
Severity: Warning
Category: Best Practices
Description
One should always prioritize using a string literal as the first arguments in any string comparison. This approach serves as a preventive measure against NullPointerExceptions because when the second argument is null, instead of encountering an exception, the comparisons will simply yield false results.
Non-Compliant Code Examples
class Foo {
boolean bar(String x) {
return x.equals("42"); // should be "42".equals(x)
}
boolean bar(String x) {
return x.equalsIgnoreCase("42"); // should be "42".equalsIgnoreCase(x)
}
boolean bar(String x) {
return (x.compareTo("bar") > 0); // should be: "bar".compareTo(x) < 0
}
boolean bar(String x) {
return (x.compareToIgnoreCase("bar") > 0); // should be: "bar".compareToIgnoreCase(x) < 0
}
boolean baz(String x) {
return x.contentEquals("baz"); // should be "baz".contentEquals(x)
}
}
Compliant Code Examples
class Foo {
boolean bar(String x) {
return "42".equals(x);
}
boolean bar(String x) {
return "42".equalsIgnoreCase(x);
}
boolean bar(String x) {
return "bar".compareTo(x) < 0;
}
boolean bar(String x) {
return "bar".compareToIgnoreCase(x) < 0;
}
boolean baz(String x) {
return "baz".contentEquals(x);
}
}
