I am thinking of creating a debug tool for my Java application. I am wondering if it is possible to get a stack trace, just like Exception.printStackTrace() but without actually throwing an exception? My goal is to, in any given method, dump a stack to see who the method caller is. 10 Answers 10
How do I convert a long to a byte[] and back in Java? I’m trying convert a long to a byte[] so that I will be able to send the byte[] over a TCP connection. On the other side I want to take that byte[] and convert it back into a double. 16 Answers 16
I am trying to import Gradle project in Intellij Idea with local Gradle distrib and getting stacktrace with the following message: Could not target platform: ‘Java SE 8’ using tool chain: ‘JDK 7 (1.7)’. Could anyone explain please what could be the reason? 13 Answers 13
How do I get up to the first n characters of a string in Java without doing a size check first (inline is acceptable) or risking an IndexOutOfBoundsException? 7 Answers 7
Currently in an Android application that I’m developing I’m looping through the pixels of an image to blur it. This takes about 30 seconds on a 640×480 image. While browsing apps in the Android Market I came across one that includes a blur feature and their blur is very fast (like 5 seconds) so they … Read more
I am trying to use the org.springframework.orm.jdo.TransactionAwarePersistenceManagerFactoryProxy in my Spring project, but I am not sure how to use it or whether it’s exactly what I am looking for. I realize it can help make my DAOs work with a plain JDO PersistenceManagerFactory. Another question is: what happens if the proxy doesn’t get made properly? … Read more
public static ArrayList mainList = someList; How can I get a specific item from this ArrayList? mainList[3]? 8 Answers 8
I encountered a situation where a non-void method is missing a return statement and the code still compiles. I know that the statements after the while loop are unreachable (dead code) and would never be executed. But why doesn’t the compiler even warn about returning something? Or why would a language allow us to have … Read more
I want to split a string by ‘=’ charecter. But I want it to split on first instance only. How can I do that ? Here is a JavaScript example for ‘_’ char but it doesn’t work for me split string only on first instance of specified character Example : apple=fruit table price=5 When I … Read more
When reading JDK source code, I find it common that the author will check the parameters if they are null and then throw new NullPointerException() manually. Why do they do it? I think there’s no need to do so since it will throw new NullPointerException() when it calls any method. (Here is some source code … Read more
