Filter class and turns it into collection

FilterMapTest.java

import static com.google.common.collect.Maps.filterEntries;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import org.junit.Assert;
import org.junit.Test;

import com.google.common.base.Predicate;

public class FilterMapTest {

  public static Collection<String> filtreMapByKeyToCollection(Map<String, String> map) {
    Predicate<Entry<String, String>> keyStartWithOption = new Predicate<Entry<String, String>>() {
      @Override
      public boolean apply(Entry<String, String> o) {
        if (o != null && o.getKey().startsWith("option_"))
          return true;
        return false;
      }
    };
    return filterEntries(map, keyStartWithOption).values();
  }

  @Test
  public void filtreMapTest() {
    Map<String, String> options = new HashMap<String, String>();
    options.put("option_1", "valeur 1");
    options.put("option_2", "valeur 2");
    options.put("anotherKey", "whatever");
    options.put("anotherKey", null);
    long start = System.currentTimeMillis();
    Collection<String> filtredOption = filtreMapByKeyToCollection(options);
    System.out.println(System.currentTimeMillis() - start + " ms");
    Assert.assertFalse(filtredOption.contains("whatever"));
    Assert.assertTrue(filtredOption.contains("valeur 1"));

  }

}