FileFiles.java

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class FileFiles {
    public static void main(final String[] args) throws IOException {
        final File ofFile = File.createTempFile("fooA/barA", ".tmp", new File("/tmp"));
        System.out.println(ofFile.toString());

        Path ofFiles1 = null;
        try {
            ofFiles1 = Files.createTempFile(Paths.get("/tmp"), "fooB/barB", ".tmp");
        } catch (final IllegalArgumentException ex) {
            System.out.println(ex.toString());
        }
        if (ofFiles1 != null) {
            System.out.println(ofFiles1.toString());
        }

        Path ofFiles2 = null;
        try {
            ofFiles2 = Files.createTempFile(Paths.get("/tmp"), "fooC", ".tmp");
        } catch (final IllegalArgumentException ex) {
            System.out.println(ex.toString());
        }
        if (ofFiles2 != null) {
            System.out.println(ofFiles2.toString());
        }
    }
}

/tmp/barA9003569178568216717.tmp
java.lang.IllegalArgumentException: Invalid prefix or suffix
/tmp/fooC8565011042349501175.tmp