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String regex replace using capture groups

Since Java SE 9, java.util.regex.Matcher’s replaceAll() method supports lambda expressions.

// import java.util.regex.*;
String varName = "random_string";
Pattern pattern = Pattern.compile("_([a-z])");
Matcher matcher = pattern.matcher(varName);
String result = matcher.replaceAll(m -> m.group(1).toUpperCase());

Source: Arvind Kumar Avinash’s answer on Stack Overflow

Check characters properties using Character’s static methods

The Character class provides some static predicates like

• isAlphabetic(char c)
• isDigit(char c)
• isLowerCase(char c)

Source: Java Character isAlphabetic() Method on Javapoint