All Java String Methods

Java’s String class is huge — it has over 60 methods in modern versions — so I’ll give you a complete, well-organized list of the most important ones, grouped by category, so it’s easy to study for interviews or coding.

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1️⃣ Length, Empty Check, and Comparison

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2️⃣ Searching in Strings

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3️⃣ Extracting Substrings

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4️⃣ Modifying / Creating New Strings

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5️⃣ Trimming & Stripping

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6️⃣ Changing Case

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7️⃣ Splitting and Joining

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8️⃣ Conversion Methods

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9️⃣ Checking Matches

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🔟 Other Utility Methods

I’ll make it organized by category, so it’s easy to follow and copy into your IDE.

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javaCopyEditpublic class AllStringMethodsExample {
    public static void main(String[] args) {

        // 1️⃣ Length, Empty Check, and Comparison
        String s1 = "Hello";
        String s2 = "hello";
        System.out.println("length(): " + s1.length());
        System.out.println("isEmpty(): " + "".isEmpty());
        System.out.println("isBlank(): " + "   ".isBlank()); // Java 11+
        System.out.println("equals(): " + s1.equals(s2));
        System.out.println("equalsIgnoreCase(): " + s1.equalsIgnoreCase(s2));
        System.out.println("compareTo(): " + s1.compareTo(s2));
        System.out.println("compareToIgnoreCase(): " + s1.compareToIgnoreCase(s2));

        // 2️⃣ Searching
        String str = "Java Programming";
        System.out.println("charAt(2): " + str.charAt(2));
        System.out.println("indexOf('a'): " + str.indexOf('a'));
        System.out.println("indexOf(\"Pro\"): " + str.indexOf("Pro"));
        System.out.println("indexOf('a', 2): " + str.indexOf('a', 2));
        System.out.println("lastIndexOf('a'): " + str.lastIndexOf('a'));
        System.out.println("contains(\"Java\"): " + str.contains("Java"));
        System.out.println("startsWith(\"Java\"): " + str.startsWith("Java"));
        System.out.println("startsWith(\"Program\", 5): " + str.startsWith("Program", 5));
        System.out.println("endsWith(\"ing\"): " + str.endsWith("ing"));

        // 3️⃣ Substring extraction
        String subStr = "Automation";
        System.out.println("substring(5): " + subStr.substring(5));
        System.out.println("substring(0,4): " + subStr.substring(0, 4));
        System.out.println("subSequence(0,4): " + subStr.subSequence(0, 4));

        // 4️⃣ Modifying / Creating
        String modStr = "Hello World";
        System.out.println("concat(): " + modStr.concat("!!!"));
        System.out.println("replace(char,char): " + modStr.replace('l', 'x'));
        System.out.println("replace(seq,seq): " + modStr.replace("World", "Java"));
        System.out.println("replaceAll(): " + modStr.replaceAll("\\s", "_"));
        System.out.println("replaceFirst(): " + modStr.replaceFirst("l", "X"));
        System.out.println("repeat(3): " + "Hi ".repeat(3)); // Java 11+

        // 5️⃣ Trimming & Stripping
        String spaced = "   Hello Java   ";
        System.out.println("trim(): '" + spaced.trim() + "'");
        System.out.println("strip(): '" + spaced.strip() + "'"); // Java 11+
        System.out.println("stripLeading(): '" + spaced.stripLeading() + "'");
        System.out.println("stripTrailing(): '" + spaced.stripTrailing() + "'");

        // 6️⃣ Changing Case
        String caseStr = "Java";
        System.out.println("toLowerCase(): " + caseStr.toLowerCase());
        System.out.println("toUpperCase(): " + caseStr.toUpperCase());

        // 7️⃣ Splitting & Joining
        String csv = "apple,banana,orange";
        String[] fruits = csv.split(",");
        System.out.println("split():");
        for (String f : fruits) System.out.println(" - " + f);
        System.out.println("String.join(): " + String.join("-", "2025", "08", "13"));

        // 8️⃣ Conversion
        String convStr = "Hello";
        char[] chars = convStr.toCharArray();
        System.out.print("toCharArray(): ");
        for (char c : chars) System.out.print(c + " ");
        System.out.println();
        byte[] bytes = convStr.getBytes();
        System.out.println("getBytes(): " + bytes.length + " bytes");
        System.out.println("String.valueOf(): " + String.valueOf(123));
        char[] arr = {'J', 'a', 'v', 'a'};
        System.out.println("String.copyValueOf(): " + String.copyValueOf(arr));

        // 9️⃣ Matching
        String matchStr = "Java123";
        System.out.println("matches(): " + matchStr.matches("Java\\d+"));
        System.out.println("regionMatches(): " + matchStr.regionMatches(0, "JavaScript", 0, 4));

        // 🔟 Other Utilities
        String formatted = String.format("My name is %s, age %d", "Sam", 25);
        System.out.println("String.format(): " + formatted);
        String text = "Hello\\nWorld";
        System.out.println("translateEscapes(): " + text.translateEscapes()); // Java 15+
        String transformed = "java".transform(s -> s.toUpperCase() + " LANGUAGE"); // Java 12+
        System.out.println("transform(): " + transformed);
    }
}

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How this helps you

• Covers almost every important String method from Java 8 to Java 17.

• Grouped logically (comparison, search, modify, trim, case, split/join, convert, match, utilities).

• Can be run directly — no extra dependencies.

• Output shows exact effect of each method, which helps in interviews.