The ``++equals++`` and ``++hashCode++`` methods of ``++java.net.URL++`` both may trigger a name service (usually DNS) lookup to resolve the host name or IP address. Depending on the configuration, and network status, that can take a long time. ``++URI++`` on the other hand makes no such calls and should be used instead unless the specific ``++URL++`` functionality is required.


In general it is better to use the ``++URI++`` class until access to the resource is actually needed, at which point you can just convert the ``++URI++`` to a ``++URL++`` using ``++URI.toURL()++``.


This rule checks for uses of ``++URL++`` 's in ``++Map++`` and ``++Set++`` , and for explicit calls to the ``++equals++`` and ``++hashCode++`` methods.

== Noncompliant Code Example

----
public void checkUrl(URL url) {
  Set<URL> sites = new HashSet<URL>();  // Noncompliant

  URL homepage = new URL("http://sonarsource.com");  // Compliant
  if (homepage.equals(url)) { // Noncompliant
    // ...
  }
}
----

== Compliant Solution

----
public void checkUrl(URL url) {
  Set<URI> sites = new HashSet<URI>();  // Compliant

  URI homepage = new URI("http://sonarsource.com");  // Compliant
  URI uri = url.toURI();
  if (homepage.equals(uri)) {  // Compliant
    // ...
  }
}
----