Why there is no main method in Servlet?

A Java Servlet is a plugin to a web server and always run in web container.

When we run any program that has main method, the program runs the web server with the help of main method. And a web server runs the Servlet.

Simple Spring project example

Create a implementation class ImplCode.java

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import org.springframework.context.ApplicationContext; import org.springframework.context.support.FileSystemXmlApplicationContext; public class ImplCode { public static void main(String[] args) { ApplicationContext appContext=new FileSystemXmlApplicationContext("AppContextBeanFile.xml"); Fruit fruit=appContext.getBean("fruit", Fruit.class); Vegetable veg=(Vegetable) appContext.getBean("veg"); System.out.println(fruit.whoareyou()); System.out.println(veg.whoareyou()); } }

Create a bean class Vegetable.java

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package rashiddemo; public class Vegetable { public String whoareyou() { String intro="I am vegetable!!"; return intro; } }

Create another bean class Fruit.java

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package rashiddemo; public class Fruit { public String whoareyou() { String intro="I am fruit!"; return intro; } }

Create a AppContextBeanFile.xml and add your bean classes using bean tag.

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<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <bean id="fruit" class="rashiddemo.Fruit"></bean> <bean id="veg" class="rashiddemo.Vegitable"></bean> </beans>

OpenJDK 64-Bit Error Not enough space | errno=12

[ERROR] OpenJDK 64-Bit Server VM warning: INFO: os::commit_memory(0x00000000aab00000, 286261248, 0) failed; error='Not enough space' (errno=12)

Solutions

There are multiple ways through which you could fix this issue. Try any of the below step to fix the "Not enough space" error.

1. You can restart the server, this way cache will get cleared and you will get the required space for execution.

2. Increase the space for JVM or heap memory.