Deploying a WAR file gives me a 404 Status Code on Tomcat?

Question

I am fairly new to Tomcat. I just managed to build a project and exported it as a WAR file. I tried manually copying a WAR file to the Tomcat folder then restarting. It created the folder structure and everything but I get a 404 Status code when I try to reach the application. I tried deploying it through the Tomcat Admin panel but I'm seeing the same behavior. Am I doing anything fundamentally wrong?

Answer 1

Assuming that you have full privileges with the Tomcat installation, try going to http://localhost:8080/manager/html/, if you don't know the password to get into that area, look for the tomcat-users.xml file in your ${tomcat-installation}/conf directory, and that should have it. If it has no entries in it then you will want to add an entry like the following to it:

<user username="username" password="password" roles="admin,manager" /> 

See whether your application shows up in that screen, and if it does, click on the link and see if that gets you anywhere. If it doesn't, then I suggest following ifishers's advice, and looking at the log files to see if it lists any errors.

But long story short, most likely something is screwed up with your project's web.xml

Answer 2

In more recent times, this condition might occur if JAVA_HOME points to an earlier version of Java than the code in the WAR. Tomcat might use JAVA_HOME to determine JRE_HOME it shows after running startup.bat in Tomcat's BIN directory. While Tomcat may be happy itself with the Java version it gets, for the application this might not be sufficient. In my case, Tomcat 8.0.49 was running alright with JDK1.7, while the application was not initializing at all (yes, it was a Spring Boot application, WAR was being unpacked, but that's all) - without giving any errors. After setting JAVA_HOME to the location of JDK1.8, the problem was solved.