To resize an image or photo in Java use the following code:

import java.io.FileOutputStream;
import java.net.URL;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;

public class JavaRethumbExample
{
    public static void main(String [] args) throws Exception
    {
        String paramOperation = "height";
        int paramValue = 100; // New height in pixels.
        
        String imageURL = "http://images.rethumb.com/image_coimbra_600x300.jpg";
        String imageFilename = "resized-image.jpg";

        URL url = new URL(String.format("http://api.rethumb.com/v1/%s/%s/%s", paramOperation, paramValue, imageURL));
        FileOutputStream fos = new FileOutputStream(imageFilename);
        fos.getChannel().transferFrom(Channels.newChannel(url.openStream()), 0, Long.MAX_VALUE);
    }
}

Use the following commands to get started:

$ git clone https://github.com/rethumb/rethumb-java-examples.git
$ cd rethumb-java-examples
$ ... Use your IDE of choice to handle the file "resize-by-height.java"