Bat Files - Yash-777/LearnJava GitHub Wiki

@echo off
REM @echo off means avoids commented info displaying in console.
REM set "var=value"
set "CATALINA_HOME=D:\Yashwanth\D Drive\Apache\apache-tomcat-7.0.37"
echo %CATALINA_HOME%

Tomcat bin « catalina.bat

rem Guess CATALINA_HOME if not defined
set "CURRENT_DIR=%cd%"

set "%CATALINA_HOME%" == "D:\Yashwanth\D Drive\Apache\apache-tomcat-7.0.37"

rem ...

rem Ensure that any user defined CLASSPATH variables are not used on startup,
rem but allow them to be specified in setenv.bat, in rare case when it is needed.
set CLASSPATH=

rem Get standard environment variables
if not exist "%CATALINA_BASE%\bin\setenv.bat" goto checkSetenvHome
call "%CATALINA_BASE%\bin\setenv.bat"
goto setenvDone
:checkSetenvHome
if exist "%CATALINA_HOME%\bin\setenv.bat" call "%CATALINA_HOME%\bin\setenv.bat"
:setenvDone

« setenv.bat

set CATALINA_HOME = "D:\Yashwanth\D Drive\Apache\apache-tomcat-7.0.37"

set "JRE_HOME=%ProgramFiles%\Java\jdk1.6.0_45\jre"
set "JAVA_HOME=%ProgramFiles%\Java\jdk1.6.0_45"

Lock Screen

rundll32.exe user32.dll,LockWorkStation

Shutdown System

REM echo 1= 1 min
shutdown -s -t 0

Temp, Pre-fetch Clean

@echo off
del /s /f /q c:\windows\temp\*.*
rd /s /q c:\windows\temp
md c:\windows\temp
del /s /f /q C:\WINDOWS\Prefetch
del /s /f /q %temp%\*.*
rd /s /q %temp%
md %temp%
deltree /y c:\windows\tempor~1
deltree /y c:\windows\temp
deltree /y c:\windows\Prefetch
deltree /y c:\windows\tmp
deltree /y c:\windows\ff*.tmp
deltree /y c:\windows\history
deltree /y c:\windows\cookies
deltree /y c:\windows\recent
deltree /y c:\windows\spool\printers
del c:\WIN386.SWP
cls
Custom Batch file of Server start/status/stop 
#!/bin/bash
# chkconfig: 234 20 80
# description: Tomcat Server basic start/shutdown script
# processname: tomcat
#
RUNAS=admin
export JAVA_HOME=/usr/local/jdk
export TOMCAT_HOME=/opt/tomcat
export ORIENTDB_HOME=/apps/orientdb
export MLM_CONFIG_HOME=/apps/config/myapp
#export JAVA_OPTS="$JAVA_OPTS -agentlib:TakipiAgent -Xmx128m -XX:+UseConcMarkSweepGC"
export JAVA_OPTS="$JAVA_OPTS $JSSE_OPTS -Dlogging.config=/apps/config/myapp/log4j2.xml"
export JAVA_OPTS="$JAVA_OPTS -Djna.nosys=true -DdefaultCharset=UTF-8 -Dfile.Encoding=UTF-8"
#export JAVA_OPTS="$JAVA_OPTS $JSSE_OPTS -DORIENTDB_NODE_NAME=runner1 -Dlogging.config=/apps/config/myapp/log4j2.xml -Ddistributed=true"
 
#export JAVA_OPTS="$JAVA_OPTS -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Xms2048m -Xmx4096m -XX:MaxDirectMemorySize=512g"
#export JAVA_OPTS="$JAVA_OPTS -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Xms8192m -Xmx30720m -XX:MaxDirectMemorySize=512g"
#export JAVA_OPTS="$JAVA_OPTS -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Xms8192m -Xmx16384m -Dstorage.diskCache.bufferSize=14000 -XX:MaxDirectMemorySize=512g"
#export JAVA_OPTS="$JAVA_OPTS -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Xms8192m -Xmx14384m -Dstorage.diskCache.bufferSize=56000 -XX:MaxDirectMemorySize=512g -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/apps/heapdump/ -Dnetwork.http.sessionExpireTimeout=7200 -Dmail.smtp.ssl.protocols=TLSv1.2 -Dcom.sun.management.jmxremote.port=9010 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.local.only=false -Dcom.sun.management.jmxremote.rmi.port=9011 -Djava.rmi.server.hostname=localhost"
 
export JAVA_OPTS="$JAVA_OPTS -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Xms8192m -Xmx14384m -Dstorage.diskCache.bufferSize=12000 -XX:MaxDirectMemorySize=512g -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/apps/heapdump/ -Dnetwork.http.sessionExpireTimeout=7200 -Dmail.smtp.ssl.protocols=TLSv1.2"
 
#export distributed=true
 
START_TOMCAT=${TOMCAT_HOME}/bin/startup.sh
STOP_TOMCAT=${TOMCAT_HOME}/bin/shutdown.sh
 
#Tomacat-Start Command
start() {
echo `date`
echo -n "Starting tomcat: "
cd $TOMCAT_HOME
if [ `whoami` == "root" ]
then
  /sbin/runuser -l ${RUNAS}  -c ${START_TOMCAT}
else
  ${START_TOMCAT}
fi
status
}

#Tomacat-Status Command
status() {
pid=`ps aux | grep -w "tomcat"|grep -w "java" | grep -v grep | awk '{print $2}'`
if [ "$pid" == "" ]
then
  echo "Tomcat is not running"
  export stat=1
else
  numthread=`ps -efL|grep $pid|grep -v grep|wc -l`
  echo "Tomcat running on $pid...with $numthread threads"
  export stat=0
fi
}
 
#Tomacat-Stop Command
stop() {
echo `date`
status
if [ $stat -ne 0 ]
then
  echo -n
fi
echo -n "Shutting down tomcat: "
cd $TOMCAT_HOME
if [ `whoami` == "root" ]
then
  /sbin/runuser -l  ${RUNAS}  -c ${STOP_TOMCAT}
else
  ${STOP_TOMCAT}
fi
echo "Waiting 40 seconds..."
waited=0
while [ $waited -le 40 ]
do
  sleep 5
  status
  if [ $stat -eq 0 ]
  then
   waited=$((waited+5))
   echo Waited $waited seconds...
  else
   waited=45
  fi
done
if [ $waited -gt 40 ]
then
  kill -9 $pid 2> /dev/null
fi
echo "done."
}
 
case "$1" in
start)
  start
;;
stop)
  stop
;;
restart)
  stop
  start
;;
status)
  status
;;
*)
  echo "Usage: $0 {start|stop|restart|status}"
esac
exit 0

OpenJDK Downloads : In a class-based object-oriented language, in general, state is carried by instances, methods are carried by classes, and inheritance is only of structure and behavior. Basic, Refactoring Techniques

Method signature: It consists of method name and parameter list (number/type/order of the parameters). methodName(parametersList y). An instance method in a subclass with the same signature and return type as an instance method in the super-class overrides the super-class's method.

Java OOP concepts
Class  - Collection of a common features of a group of object [static/instance Fields, blocks and Methods]
Object - Instance of a class (instance fields)
Abstraction - Process of hiding complex info and providing required info like API, Marker Interfaces ...
Encapsulation(Security) - Class Binding up with data members(fields) and member functions.
Inheritance  (Reusability by placing common code in single class)
 1. Multilevel - {A -> B -> C} 2. Multiple - Diamond problem {A <- (B) -> C} [Java not supports] 3. Cyclic {A <-> B} [Java not supports]
 * Is-A   Relation - Class A extends B
 * Hash-A Relation - Class A { B obj = new B(); } - (Composition/Aggregation)
Polymorphism (Flexibility) 1. Compile-Time Overloading    2. Runtime Overriding  [Greek - "many forms"]


int[] arr = {1,2,3}; int arrLength = arr.length;   // Fixed length of sequential blocks to hold same data type
String str = "Yash"; int strLength = str.length(); // Immutable Object value can't be changed.

List<?> collections = new ArrayList<String>(); int collectionGroupSize = collections.size();
Map<?, ?> mapEntry = new HashMap<String, String>();
Set<?> keySet = mapEntry.keySet(); // Set of Key's
Set<?> entrySet = mapEntry.entrySet(); // Set of Entries [Key, Value]

// Immutable Objects once created they can't be modified. final class Integer/String/Employee
Integer val = Integer.valueOf("100"); String str2 = String.valueOf(100); // Immutable classes
final class Employee { // All Wrapper classes, java.util.UUID, java.io.File ...
    private final String empName; // Field as Final(values can be assigned only once) Only getter functions.
    public Employee(String name) { this.empName = name; }
}

Native Java Code for Hashtable.h, Hashtable.cpp SQL API.

You can check your current JDK and JRE versions on your command prompt respectively,

  • JDK javac -version [C:\Program Files\Java\jdk1.8.0_121\bin] o/p: javac 1.8.0_121
  • JRE java -version [C:\Program Files\Java\jdk1.8.0_121\bin] o/P: java version "1.8.0_102"

JAVA_HOME - Must be set to JDK otherwise maven projects leads to compilation error. [ERROR] No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK? C:\Softwares\OpenJDK\, 7-zip

Fatal error compiling: invalid target release: JRE and JDK must be of same version 1.8.0.XXX

Disable TLS 1.0 and 1.1security-libs/javax.net.ssl: TLS 1.0 and 1.1 are versions of the TLS protocol that are no longer considered secure and have been superseded by more secure and modern versions (TLS 1.2 and 1.3).

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