Performance Testing and Engineering

 Creating java file Open note pad and write simple java  program and save as with .java extension. ex: java code: class HelloWorld {     public static void main(String[] args) {         System.out.println("Hello, World!!");      } } save the text file with extension as .java Creating class file compiling java program through command prompt Class file will be created in the same folder after successful compilation of java file Create a manifest txt file with class names ex: NOTE: Space should be provided as highlighted in yellow Command to convert java program to jar file Execute jar file from Command prompt  

http://eyeontesting.com/questions/1272/an-operation-was-attempted-on-something-that-is-no.html

In this blog, I’ll tell you how to load test the oracle database using loadrunner. There are different ways to achieve it and one simple way is writing SQL queries in vugen script. In this blog I’m going to tell how to connect to database, how to execute query and how to disconnect. I will be using lr_db functions to achieve this. Loadrunner help is very useful with details about lr_db functions. Connect to Oracle database: lr_db_connect("StepName=Connect",         "ConnectionString=Provider=OraOLEDB.Oracle; dbq=10.xx.xx.xx:1540; Data Source=XXXX; Persist Security Info=True; User ID=username; Password=password",         "ConnectionName=OracleDB",         "ConnectionType=OLEDB", LAST ); SQL statement: lr_db_executeSQLStatement("StepName=PerformQuery",                 "ConnectionName= OracleDB",                 "SQLStatement=SELECT * FROM \"TableName\" ",                 &q

Here are the top 7 Command tools which are very useful to monitor and debug Linux System Performance which are frequently used command line to monitor Linux system performance. TOP - LINXU PROCESS MONITORING It display CPU usage, Memory usage, Swap Memory, Cache Size, Buffer Size, Process PID, User, Commands and much more. It also shows high memory and cpu utilization of a running processess. The top command is much userful for system administrator to monitor and take correct action when required. Let’s see top command in action. # top VMSTAT – VIRTUAL MEMORY STATISTICS Linux VmStat command used to display statistics of virtual memory, kernerl threads, disks, system processes, I/O blocks, interrupts, CPU activity and much more.  # vmstat TCPDUMP – NETWORK PACKET ANALYZER Tcpdump one of the most widely used command-line network packet analyzer or packets sniffer program that is used capture or filter TCP/IP packets that received or transferred on a specific

Main causes of Out-Of-Memory Errors When there is no enough space to create a new object in heap JVM through a Out-of-memory errors before giving this error JVM surly runs garbage collector once to check for available memory which can be freed .The main causes for this error can be. It is possible that you have estimate less memory for your application for example your application need 2 Gb of memory but you have configured only 512 Mb so here you will get an OOME(Out-of-memory errors )  1.Due to Memoryleak :- Memory leak is responsible for decreasing the available memory for heap and can lead to out of memory error for more read What is a Memory Leak in java?  2.Memory fragmentation :- It is possible that there may be space in heap but it may be not contiguous . And heap needs compaction . Rearrange its memory. 3.Excess GC overhead :- Some JVM implementations, such as the Oracle HotSpot, will throw an out-of-memory error when GC overhead becomes too great. This feature

The  web_set_max_html_param_len  function sets the maximum length of any HTML string which VuGen can retrieve and save in a parameter. The default value for the maximum length of a parameter that can be captured during correlation is 256 characters. To retrieve a string longer than 256 characters, use  web_set_max_html_param_len  to increase the maximum valid length. An attempt to save a string whose length exceeds the maximum length will fail