import java.util.Map;
 
public class Getenv{
    public static void main(String args[]){
        for (Map.Entry<String, String> env : System.getenv().entrySet()) {
            System.out.println(env.getKey() + " : " + env.getValue());
        }
    }
}

import org.apache.commons.lang.builder.ToStringBuilder;
 
public class VarDump{
    public static void main(String args[]){
        System.out.println(ToStringBuilder.reflectionToString(args));
    }
}

hoge=fuga
hello=world

import java.io.File;
import java.io.FilenameFilter;
 
public class ListFiles{
    public static void main(String args[]){
        File directory = new File(args[0]);
        for(File file : directory.listFiles(getRegexFilter(".*\\.xls"))){
            System.out.println(file.getAbsolutePath());
        }
    }
 
    private static FilenameFilter getRegexFilter(String regex) {
        final String regex_ = regex;
        return new FilenameFilter() {
            public boolean accept(File dir, String name) {
                return name.matches(regex_);
            }
        };
    }
}