Ali failed on three sides

--------Update 2015-04-16

In Tomcat next, using ClassLoader to load class information will be placed in a class of method areas (permanent generation).

When this class creates a thread, for example, displays the current time period, this can cause this information to already exist in the region for a long period, and is finished. But it doesn't end up with this additional thread. So, assuming that this class was started multiple times by Tomcat, it would cause Oom to fill up the Tomcat's permanent zone.

This is also the memory leak in the permanent zone.

The relationship between Tomcat and multiple Web application.

Tomcat is a process, which is a JVM. The Web App is a resource file.

Different webapp corresponding to different monitoring port. So a tomcat loads different resources by accepting different listening ports.

All of these resources are loaded into the permanent zone. This results in a memory leak in the permanent zone.

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At nine in the morning, I received a telephone call from Hangzhou, and Ali came on three sides.

First, or introduce the next CityGo. Probably got a look at the background of the project.

One of the places of failure. I introduce the background of this game too much crap. What Tsinghua University, such as, should not say these, but should highlight their short time high-quality finished.

Asked how to store travel notes, now is still directly stored, nothing special place.

Asked in the data volume when how to infer what travels around, answer according to the District to divide, (in Xi ' an, according to the district to be divided or feasible, the interviewer said to Hangzhou is not feasible, but should follow the principle of the map, according to latitude and longitude to the map into a piece. 1. I have not been to Hangzhou, 2. A piece of the same as in accordance with the central sense of the administrative district, is the classification.

）

Asked what difficulties encountered in the project, this problem in front of both sides have encountered, I should be a good summary of the problem.

Asked about familiar programming languages, C + + and Java memory management, common data structures. Process communication.

Here I feel the failure of the second place. I said it as a whole and didn't go into it, and the interviewer didn't answer (I was waiting for him to ask questions), did he give him a feeling that I just knew about it.

You should go through each point in the future instead of waiting for the interviewer to ask questions.

Whether there is a memory leak in Java, answer No, wrong!

Asked the difference and detailed implementation of HashMap Hashtable, the answer is thread-safe and insecure. Detailed implementation of their own test is based on the operating system of mutual exclusion to maintain, have not met, and then take a good grasp of a piece.

General summary. preparation is still insufficient. Need to be prepared to be targeted, the answer skills should be improved.

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Ali failed on three sides