how to make a string all caps in java code example

Example: string to uppercase

const upperCase = function(names){
    const toLower = names.toLowerCase().split(' ');
    const namesUpper = [];
    for(const wordName of toLower){
        namesUpper.push(wordName[0].toUpperCase() + wordName.slice(1));
    }
    return namesUpper.join(' ');
}