Language

Text blocks for multiline strings

Old String json = "{\n" + " \"name\": \"Duke\",\n" + " \"age\": 30\n" + "}";

Modern String json = """ { "name": "Duke", "age": 30 }""";

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JDK 15+ learn more →

Strings

String.isBlank()

Old boolean blank = str.trim().isEmpty(); // or: str.trim().length() == 0

Modern boolean blank = str.isBlank(); // handles Unicode whitespace too

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JDK 11+ learn more →

Strings

String.strip() vs trim()

Old // trim() only removes ASCII whitespace // (chars <= U+0020) String clean = str.trim();

Modern // strip() removes all Unicode whitespace String clean = str.strip(); String left = str.stripLeading(); String right = str.stripTrailing();

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JDK 11+ learn more →

Strings

String.repeat()

Old StringBuilder sb = new StringBuilder(); for (int i = 0; i < 3; i++) { sb.append("abc"); } String result = sb.toString();

Modern String result = "abc".repeat(3); // "abcabcabc"

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JDK 11+ learn more →

Strings

String.indent() and transform()

Old String[] lines = text.split("\n"); StringBuilder sb = new StringBuilder(); for (String line : lines) { sb.append(" ").append(line) .append("\n"); } String indented = sb.toString();

Modern String indented = text.indent(4); String result = text .transform(String::strip) .transform(s -> s.replace(" ", "-"));

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JDK 12+ learn more →

Strings

String.formatted()

Old String msg = String.format( "Hello %s, you are %d", name, age );

Modern String msg = "Hello %s, you are %d" .formatted(name, age);

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JDK 15+ learn more →

Strings

String chars as stream

Old for (int i = 0; i < str.length(); i++) { char c = str.charAt(i); if (Character.isDigit(c)) { process(c); } }

Modern str.chars() .filter(Character::isDigit) .forEach(c -> process((char) c));

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JDK 9+ learn more →

Strings

String.lines() for line splitting

Old String text = "one\ntwo\nthree"; String[] lines = text.split("\n"); for (String line : lines) { System.out.println(line); }

Modern String text = "one\ntwo\nthree"; text.lines().forEach(IO::println);

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JDK 11+ learn more →

Date/Time

HexFormat

Old // Pad to 2 digits, uppercase String hex = String.format( "%02X", byteValue); // Parse hex string int val = Integer.parseInt( "FF", 16);

Modern var hex = HexFormat.of() .withUpperCase(); String s = hex.toHexDigits( byteValue); byte[] bytes = hex.parseHex("48656C6C6F");

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JDK 17+ learn more →