Question

EDIT: it turned out this question had been asked the wrong way — see my answer below. Please vote to close it.

For a unit test, I need to make the new java.net.URL(String) constructor throw a MalformedURLException, but it takes an awfully long time for what it does — 2.5 seconds.

I understand this is probably related to an attempt to create a protocol handler, so I tried specifying no protocol handler, e.g.:

new URL(null);
new URL("://");
new URL("/abc");

I briefly looked through the implementation, it seems to be preparsing the URL string to eliminate obvious errors. Why does it take so long, even with “null”?

Answer 1

Could it be something else causing the delay? I can’t reproduce this:

public class UrlTest {

    static public void urltest(String s) {
        long start = System.currentTimeMillis();
        try {
            new URL(s);
            System.out.println("successfully created URL after "+(System.currentTimeMillis()-start)+" milliseconds. URL: "+s);
        } catch(Exception e) {
            System.out.println(e.toString()+" after "+(System.currentTimeMillis()-start)+" milliseconds. URL: "+s);         
        }
    }

    static public void main(String[] args) {
        System.out.println(System.getProperty("java.version"));
        urltest(null);
        urltest("://");
        urltest("/abc");

    }
}

Output:

1.6.0_18-ea
java.net.MalformedURLException after 0 milliseconds. URL: null
java.net.MalformedURLException: no protocol: :// after 1 milliseconds. URL: ://
java.net.MalformedURLException: no protocol: /abc after 0 milliseconds. URL: /abc

Regarding equals(), this is from the javadoc:

Two hosts are considered equivalent if both host names can be resolved into the same IP addresses; else if either host name can’t be resolved, the host names must be equal without regard to case; or both host names equal to null.

Since hosts comparison requires name resolution, this operation is a blocking operation.

Note: The defined behavior for equals is known to be inconsistent with virtual hosting in HTTP.