The internal connection pool has reached its maximum size and no connection is currently available!

You should comment this line in hibernate.cfg.xml

 <!--  <property name="connection.pool_size">1</property> -->

Can not find the tag library descriptor for "http://java.sun.com/jsp/jstl/core"

You would have used this way
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core"  prefix="c" %>

You should use this, prefix should come first
    <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

Main thing is you will be using tomcat 7 or higher version. You need to use JSTL - 1.2.jar

you  might be simply using JSTL.jar.

just put the JSTL-1.2.jar in lib folder..

how to close the port in computer?

To check the ports open in your computer,

go to cmd, type netstat.

you will get all the ports used in the computer..

If you want to close the port used, netstat -a -n -o in cmd...

you will get the PID. Note this PID go to task manager and kill it..

how to check how many tables are there in database in oracle?

select * from user_tables;

How to check schema in mysql?

Use schema_name;
desc table_name;

How to show current Workspace in Eclipse?

Go to eclipse folder,

1.Edit the eclipse.ini.
2.add -showlocation
3.This should be before -startup



-showlocation
-startup
plugins/org.eclipse.equinox.launcher_1.3.0.v20130327-1440.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.win32.win32.x86_64_1.1.200.v20140116-2212
-product

Files\Java\jdk1.8.0_112 was unexpected at this time.

Its problem with your JAVA_HOME. you would have set your JAVA_HOME with double quotes.

How to set java_home and java_path?

After installing java,  we need to set the java home and path..

you can set it in two ways, one through screen and other with cmd.

I will show you how to set it through cmd..

set JAVA_HOME=your java path without bin

set PATH=%path%;your java path with bin

you should not leave any space in between after PATH or JAVA_HOME..

you can check the path using echo command

In the screenshot I made mistake by giving double quotes..

if you use double quotes, u will get this error Files\Java\jdk1.8.0_112 was unexpected at this time in future

java was started by returned exit code=13

Which mean you are using 64 bit eclipse and you have installed 32 bit java..

Uninstall 32 bit java and install 64 bit java...

How to clear the cmd (command prompt) screen?

Use cls command to clear the cmd screen.