StringequalsIgnoreCase

StringequalsIgnoreCase refers to a method in Java’s String class, commonly written as equalsIgnoreCase. It performs a case-insensitive comparison of the invoking string with another string. The method returns true when both strings represent the same characters in the same order, ignoring differences in case, and false otherwise. It is widely used for user input matching, command parsing, and similar tasks where exact case should not affect equality.

In Java, equalsIgnoreCase has the signature public boolean equalsIgnoreCase(String anotherString). If anotherString is null, the method returns false. The comparison proceeds by evaluating each corresponding character pair according to Unicode case mappings; the method does not use locale-specific rules. If the strings have different lengths, the result is false. For performance, the method includes optimizations for common ASCII cases, but in general it may be slower than a simple equals followed by a case-normalization step for many characters.

Note that equalsIgnoreCase is locale-insensitive and is not affected by the default locale. It does not support locale-aware case folding like some languages require; for locale-sensitive comparisons, developers can use alternatives such as Collator with a specific Locale or convert strings using a Locale-aware approach before comparing.

Example: String a = "Hello"; String b = "hello"; boolean same = a.equalsIgnoreCase(b); // true