Java - How to repeat a string n number of times?

Java String Manipulation Java 

This tutorial shows different ways to repeat an input string n number of times.

By using InputStream#range()

package com.logicbig.example;

import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class StringRepeat {
    public static void main(String[] args) {
        String s = stringRepeat("=", 10);
        System.out.println(s);
    }

    private static String stringRepeat(String input, int n) {
        return IntStream.range(0, n)
                        .mapToObj(i -> input)
                        .collect(Collectors.joining());
    }
}

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By using Stream#generate()

package com.logicbig.example;

import java.util.stream.Collectors;
import java.util.stream.Stream;

public class StringRepeat1 {
    public static void main(String[] args) {
        String s = stringRepeat("=", 10);
        System.out.println(s);
    }

    private static String stringRepeat(String input, int n) {
        return Stream.generate(() -> input)
                     .limit(n)
                     .collect(Collectors.joining());
    }
}

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By using Collections#nCopies()

package com.logicbig.example;

import java.util.Collections;
import java.util.stream.Collectors;

public class StringRepeat2 {
    public static void main(String[] args) {
        String s = stringRepeat("=", 10);
        System.out.println(s);
    }

    private static String stringRepeat(String input, int n) {
        return Collections.nCopies(n, input)
                          .stream()
                          .collect(Collectors.joining());

    }
}

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By using StringBuilder#append()

package com.logicbig.example;

public class StringRepeat3 {
    public static void main(String[] args) {
        String s = stringRepeat("=", 10);
        System.out.println(s);
    }

    private static String stringRepeat(String input, int n) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < n; i++) {
            sb.append(input);
        }
        return sb.toString();
    }
}

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By using Java 11 String#repeat()

package com.logicbig.example;

public class StringRepeat4 {
    public static void main(String[] args) {
        String s = stringRepeat("=", 10);
        System.out.println(s);
    }

    private static String stringRepeat(String input, int n) {
        return input.repeat(n);
    }
}

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By using Apache common-lang's StringUtils#repeat()

pom.xml

<dependency>
   <groupId>org.apache.commons</groupId>
   <artifactId>commons-lang3</artifactId>
   <version>3.10</version>
</dependency>

package com.logicbig.example;

import org.apache.commons.lang3.StringUtils;

public class StringRepeat6 {
    public static void main(String[] args) {
        String s = stringRepeat("=", 10);
        System.out.println(s);
    }

    private static String stringRepeat(String input, int n) {
        return StringUtils.repeat(input, n);
    }
}

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By using String#concat() recursively

package com.logicbig.example;

public class StringRepeat8 {
    public static void main(String[] args) {
        String s = stringRepeat("=", 10);
        System.out.println(s);
    }

    private static String stringRepeat(String input, int n) {
        return n > 1 ?
                input.concat(stringRepeat(input, n - 1)) :
                input;
    }
}

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By using String#concat() in a loop

package com.logicbig.example;

public class StringRepeat9 {
    public static void main(String[] args) {
        String s = stringRepeat("=", 10);
        System.out.println(s);
    }

    private static String stringRepeat(String input, int n) {
        String result = "";
        for (int i = 0; i < n; i++) {
            result = result.concat(input);
        }
        return result;
    }
}

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By using Arrays#fill()

package com.logicbig.example;

import java.util.Arrays;
import java.util.stream.Collectors;

public class StringRepeat10 {
    public static void main(String[] args) {
        String s = stringRepeat("=", 10);
        System.out.println(s);
    }

    private static String stringRepeat(String input, int n) {
        String[] strings = new String[n];
        Arrays.fill(strings, input);
        return Arrays.stream(strings).collect(Collectors.joining());
    }
}

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