МІкрооптимізації в Java. String equals

StringCharEqual.java

@BenchmarkMode(Mode.AverageTime)
@Fork(1)
@State(Scope.Thread)
@Warmup(iterations = 5, time = 1)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Measurement(iterations = 10, time = 1)
public class EqualChar {

   @Param({"/", "/my/server/url"})
   private String url;

   @Benchmark
   public boolean equalsPost() {
       return url != null && url.equals("/");
   }

   @Benchmark
   public boolean equalsPre() {
       return "/".equals(url);
   }

   @Benchmark
   public boolean equalsOptimized() {
       return equalsOneChar(url);
   }

   private static boolean equalsOneChar(String url) {
       return url != null && url.length() == 1 && url.charAt(0) == '/';
   }

}