Willing wheels

When loading external classes using RMI, it is key to compile against same jars as the ones used in target system. If not, RMi local class incompatible error can be thrown because class id between two jar compilations will be different. As such serialization and de serialization will not work properly, throwing this error. Re-mediation is to always fetch jars corresponding to the environment against which app is developed and place them in the classpath. sources http://craftingjava.blogspot.com.au/2012/06/javaioinvalidclassexception-local-class.html http://www.coderanch.com/t/571958/java/java/Invalid-Class-Exception-serialization http://docs.oracle.com/javase/tutorial/rmi/compiling.html

Identifed steps to import dump on Oracle Database 11g Express Edition Release 11.2.0.2.0 – 64bit Production Step 1. log in as sysadmin all steps below are to be done when logged as sysadmin (username: SYS, pwd:XXX) in case password is forgotten, log into oracle box with user used to install oracle and no password will be asked when connecting using below command line: sqlplus / as sysadmin note: if password for unix user used to install oracle is also forgottern, log in with any user then su to be root then su <user_used_to_install_oracle> Step 1. create same user as used […]

XML beautifier in linux can be easily done using libxml tools. install xml library sudo apt-get install libxml2-utils Run the following command xmllint –format –output <path_to_output> <input_file> That’s it! Apparently this tool can be used for smooth integration within gedit but this made gedit crash on my computer. sources http://www.andrejkoelewijn.com/blog/2012/04/11/formatting-xml-documents-with-gedit-and-tidy/ http://andalinux.wordpress.com/2011/11/21/pretty-printer-de-xml-en-gedit/ http://andalinux.wordpress.com/2010/07/19/gedit-avanzado-ejecutar-scripts-desde-el-editor/

Java is quite verbose and can be very frustrating when being used to more “efficient” languages. Fortunately some guys out there are trying to make things simpler… How-to list join / concatenate list of strings: StringUtils.join(List<String>, String join); // import org.apache.commons.lang3.StringUtils; split a string: StringUtils.split(String str, String sep);// import org.apache.commons.lang3.StringUtils; read entire file and store into a string (JDK 7): StringUtils.join(Files.readAllLines(Paths.get(“file”), StandardCharsets.UTF_8)); // import org.apache.commons.lang3.StringUtils; switch perspective in eclipse: CTRL+F8 CLI library: commons-cli // http://commons.apache.org/proper/commons-cli/ convert list of strings into list of integers: for(String s : strList) intList.add(Integer.valueOf(s)); list folder content: use FileUtils.listFiles from Apache commons get stack trace as […]

I am new to Java and Eclipse. After following scrupulously a tutorial to run a simple “Hello World!” app in java, when executing my very simple .java file in eclipse, I got following error: selection does not contain a main type To solve that, right click on the navigation panel on the folder containing my source file > Build Path >  Use as source folder. Bingo! Now pressing run displayed my Hello World message sources http://stackoverflow.com/questions/4252472/java-launch-error-selection-does-not-contain-a-main-type

When I tried to connect my android phone to linuxmint16 64bits, I got popup error messages: Could not display “mtp://[usb:003,021]/” Error: no such interface ‘org.gtk.vfs.Mount’ on object at path /org/gtk/vfs/mount/1 Please select another view and try again. Followed by: Unable to open MTP device ‘[usb:003,029]‘ To correct this, make sure following packages are installed sudo apt-get install mtpfs mtp-tools Update: above did not solved the issue sources http://community.linuxmint.com/software/view/mtp-tools http://community.linuxmint.com/tutorial/view/1185

Here is a very nice package to listen to tcp ports: sudo apt-get install tcpflow To activate it, run: sudo tcpflow -i any -C -e port XXXX Options may vary based on version of the tool. tcpflow -h for more details sources http://superuser.com/questions/23180/whats-the-easiest-way-to-sniff-tcp-traffic-data-on-linux

To log queries on oracle, proceed as follow: login as system (`sqlplus system`) check audit status show parameter AUDIT_TRAIL; // if NONE => no audit activated activate audit ALTER SYSTEM SET AUDIT_TRAIL=DB SCOPE=SPFILE; restart db for parameter to take effect /etc/init.d/oracle-xe restart from this point forward, activate audit on specific tables and/or actions and/or users using the AUDIT XXX statement, as `system`, run: AUDIT SELECT on userlambda.tablename // audit/log all SELECT queries on all tables db for user userlambda All audit entries are stored under sys.AUD$ table (login as system to access it). Note: to deactivate audit, run ALTER SYSTEM […]

When trying to get sqlplus client running, following error was generated: sqlplus: error while loading shared libraries: libsqlplus.so: cannot open shared object file: No such file or directory This happens because environment variable LD_LIBRARY_PATH was empty. Make it point to ./lib folder where sqlplus client was extracted and this should solve the problem. In my case, oracle sqlplus client was generated under /opt/oracle LD_LIBRARY_PATH=/opt/oracle/bin export LD_LIBRARY_PATH And voila! sources http://betterlogic.com/roger/2010/11/how-to-install-sql-plus-in-linux/

There is a great tool to identify files being access: inotifywait steps make sure inotify package is installed sudo apt-get install inotify-tools simply run inotifywait -m -r –format ‘%:e %f’ . all files being accessed will be displayed Additional filtering and output formatting options are available, `man inotifywait` for more information. Note that inotifywatch is also available, no monitor files for a given timeperiod. examples //1. listen to all events on all files (recursively) within current directory with output of type “EVENT_TYPE file_name” inotifywait -m -r –format ‘%:e %f’ . // 2. listen to event MODIFY (i.e. writing content) on […]