Given a simple XML file like this: <?xml version="1.0"?> <root id="1"> ... Calling Document.getElementById returns null (surprisingly!): import java.io.*; import org.w3c.dom.*; impo... In fact the JavaDoc says something along the lines that getElementById returns the Element that has an ID attribute with the given value. An attribute with the name "ID" or "id" is not of type ID unless it is so defined. How is an attribute defined as an ID attribute ? With a DTD or schema. If you are not validating the XML, then the API is useless. So, what to do if you want to find an element for which the attribute named "id" has a given value? Several options were offered in GetElementById Pitfalls . One of them is to...

I installed JDK 1.6 under C:\jdk1.6.0_20 and unpacked Eclipse GALILEO in C:\local\eclipse . When I launched Eclipse with eclipse.exe , it simply displayed a splash page and shutdown. Running eclipsec.exe displayed some vague errors: C:\local\eclipse>eclipsec Error occurred during... Turning on debug: C:\local\eclipse>eclipsec -debug Start VM: -Dos... The Solution: add -vm option to eclipse.ini : -startup plugins/org.eclipse.equinox.launcher_1...

You were tempted by "my fun cards" and installed "my web search" on your computer. Although some people say "my web search" is harmless, but still it behaved scary. So you want to uninstall it. You click the "Add/Remove Programs" and removed the "my web search" toolbar. But then when you type in things in the Firefox address bar you find that it still brings up "my web search"! Here's how to get rid of it: Enter "about:config" in the address bar (and promise that you'll be careful). Enter "myweb" in the filter box Reset browser.search.selectedEngine and keyword.URL , extensions.mywebsearch.openSearchURL , extensions.mywebsearch.prevKwdEnabled , and extensions.mywebsearch.prevKwdURL . The extensions.mywebsearch.* settings will be removed after Firefox restart. The parameter that affects the address bar search is keyword.URL...

The dev database keeps locking up because of failed login attempts. For a dev database, we really don't need such security measure. This is how to remove the limit. Log in as sysdba sqlplus sys@xe as sysdba Find out the profile for the user. SQL> select profile from dba_users where username ... Look at the current limits SQL> select resource_name, limit from dba_profiles... Increase the value for failed login attempts SQL> alter profile default limit failed_login_atte...

Query the dba_users view to find locked accounts. SQL> select username, account_status, lock_dat...

DBA_BLOCKERS displays a session if it is not waiting for a locked object but is holding a lock on an object for which another session is waiting. Column Datatype Description HOLDING_SESSION NUMBER Session holding a lock SQL> select * from dba_blockers; HOLDIN...

DBA_WAITERS shows all the sessions that are waiting for a lock. Column Datatype Description WAITING_SESSION NUMBER The waiting session HOLDING_SESSION NUMBER The holding session LOCK_TYPE VARCHAR2(26) The lock type MODE_HELD VARCHAR2(40) The mode held MODE_REQUESTED VARCHAR2(40) The mode requested LOCK_ID1 VARCHAR2(40) Lock ID 1 LOCK_ID2 VARCHAR2(40) Lock ID 2 SQL> set lin 120 SQL> select * from dba_wai... Or join the v$session view to find out who it is: select w.waiting_session, w.mode_requested, s.user...

If you followed the steps in Start a Java EE application with Maven , you'll arrive at an EAR file that's ready to be deployed. However, if you look carefully, you'll find that the ejb-1.0.jar file is included in the EAR file twice : once as the ejb module of the EAR, another time under the WEB-INF/lib folder of webapp-1.0.war . The second is brought about by specifying the ejb project as a dependency in the webapp POM. Actually, the webapp project is dependent on the ejb project as an EJB client. So we should have been more accurate by specifying the type of dependency as ejb-client , not ejb : Edit webapp/pom.xml , change the ejb dependency to ejb-client : <project> <modelVersion>4.0.0</modelVersion... Update ejb/pom.xml...

The class org.apache.xerces.jaxp.SAXParserFactoryImpl extends javax.xml.parsers.SAXParserFactory , so casting the former to the latter should not be a problem. This error occurs when there are two copies of javax.xml.parsers.SAXParserFactory loaded by two different class loaders, and you are trying to cast one to the other. Normally, you'll be able to find xml-apis.jar under WEB-INF/lib of the WAR file. Deleting the jar will resolve the problem. java.lang.ClassCastException: org.apache.xerces.ja...

You run an update and it hangs. Use this query to find out who's locking the table. select o.object_type, o.object_nam...