Java - String comparison

Does it give you a bellyache?
Never mind, you can compare them like this-

System.out.println(gg1.compareTo(gg3));

GWT - Highchart export request - Read multipart/form-data parameters

Getting multipart-form-data request parameters in java servlet-

Hadoop - OutOfMemoryError: Java heap space

I was writing a hadoop job which processes many files and creates multiple files from each file. I was using "MultipleOutputs" to write them. It worked fine for a small number of files but I was getting the following error for large number of files. I tried increasing the ulimit and -Xmx but to no avail.

2013-01-15 13:44:05,154 FATAL org.apache.hadoop.mapred.Child: Error running child : java.lang.OutOfMemoryError: Java heap space
    at org.apache.hadoop.hdfs.DFSOutputStream$Packet.(DFSOutputStream.java:201)
    at org.apache.hadoop.hdfs.DFSOutputStream.writeChunk(DFSOutputStream.java:1423)
    at org.apache.hadoop.fs.FSOutputSummer.writeChecksumChunk(FSOutputSummer.java:161)
    at org.apache.hadoop.fs.FSOutputSummer.flushBuffer(FSOutputSummer.java:136)
    at org.apache.hadoop.fs.FSOutputSummer.flushBuffer(FSOutputSummer.java:125)
    at org.apache.hadoop.fs.FSOutputSummer.write1(FSOutputSummer.java:116)
    at org.apache.hadoop.fs.FSOutputSummer.write(FSOutputSummer.java:90)
    at org.apache.hadoop.fs.FSDataOutputStream$PositionCache.write(FSDataOutputStream.java:54)
    at java.io.DataOutputStream.write(DataOutputStream.java:90)
    at org.apache.hadoop.mapreduce.lib.output.TextOutputFormat$LineRecordWriter. writeObject( TextOutputFormat.java:78)
    at org.apache.hadoop.mapreduce.lib.output.TextOutputFormat$LineRecordWriter. write(TextOutputFormat.java:99)
    **at org.apache.hadoop.mapreduce.lib.output.MultipleOutputs.write( MultipleOutputs.java:386)
    at com.demoapp.collector.MPReducer.reduce(MPReducer.java:298)
    at com.demoapp.collector.MPReducer.reduce(MPReducer.java:28)**
    at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:164)
    at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:595)
    at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:433)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:396)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1332)
    at org.apache.hadoop.mapred.Child.main(Child.java:262)

Solution:
I used the following configuration values to resolve it-
OPTS="-Dmapred.reduce.tasks=8 -Dio.sort.mb=640 -Dmapred.task.timeout=1200000"
hadoop jar ${JAR} ${OPTS} -src ${SRC} -dest ${DST}

GWT Celltable - Add multiple anchors to a cell

I am trying to insert multiple anchors in a single celltable cell. This is how it would look like-

The cars column has multiple cars, each car link can be clicked to perform different actions.
I have extended a MultipleAnchorCell class from AbstractSafeHtmlCell like this-



And then I use this cell in a celltable to create a column. My User class contains comma separated values of cars in a class variable.

      

       

I am still learning GWT and it took me a while to figure this out.

Comments/feedback is welcome.
===============================================================

Executing Postgres crosstab query as a prepared statement

I was executing a crosstab query as a prepared statement in Java(in a GWT app) and getting the following error -

PSQLException - Can't use query methods that take a query string on a PreparedStatement.

With some helpful folks from stackflow, I was able to resolve the error with the following code -

String query = "SELECT * FROM crosstab(
                      'SELECT rowid, a_name, value
                       FROM test WHERE a_name = ''att2''
                                    OR a_name = ''att3''
                      ORDER BY 1,2'

) AS ct(row_name text, cat_1 text, cat_2 text, cat_3 text);";

PreparedStatement stat = conn.prepareStatement(query);
ResultSet rs = stat.getResultSet();
//Note that, it is executeQuery() and not executeQuery(query)
stat.executeQuery();
rs = stat.getResultSet();
while (rs.next()) {
    //TODO
}




Thanks!