[HDFS-2331] Hdfs compilation fails

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.20.205.0, 2.0.0-alpha
• Fix Version/s: 0.20.205.0, 0.23.0
• Component/s: hdfs-client
• Hadoop Flags: Reviewed
• Assignee: Abhijit Suresh Shingate
• Reporter: Abhijit Suresh Shingate
• Created: 14/Sep/11 03:24
• Updated: 16/Mar/15 18:07
• Resolved: 15/Sep/11 08:07

Description

I am trying to perform complete build from trunk folder but the compilation fails.

Commandline:
mvn clean install

Error Message:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.
3.2:compile (default-compile) on project hadoop-hdfs: Compilation failure
[ERROR] \Hadoop\SVN\trunk\hadoop-hdfs-project\hadoop-hdfs\src\main\java\org
\apache\hadoop\hdfs\web\WebHdfsFileSystem.java:[209,21] type parameters of <T>T
cannot be determined; no unique maximal instance exists for type variable T with
upper bounds T,java.lang.Object
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e swit
ch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please rea
d the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureExc
eption
[ERROR]
[ERROR] After correcting the problems, you can resume the build with the command

This is because of known reason
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6302954

WebHdfsFileSystem.java

Following is the code snippet with issue.

  private <T> T run(final HttpOpParam.Op op, final Path fspath,
      final Param<?,?>... parameters) throws IOException {
    final HttpURLConnection conn = httpConnect(op, fspath, parameters);
    validateResponse(op, conn);
    try {
      return jsonParse(conn.getInputStream());
    } finally {
      conn.disconnect();
    }
  }

Fix to the issue

WebHdfsFileSystem.java

Following is the fix to the issue.

  private <T> T run(final HttpOpParam.Op op, final Path fspath,
      final Param<?,?>... parameters) throws IOException {
    final HttpURLConnection conn = httpConnect(op, fspath, parameters);
    validateResponse(op, conn);
    try {
      return WebHdfsFileSystem.<T>jsonParse(conn.getInputStream());
    } finally {
      conn.disconnect();
    }
  }

Issue Links

• duplicates: HDFS-2329 HDFS-2317 in trunk appears to have broken the build