I am confused about sharing arrays safely between threads in Java, specifically memory fences and the keyword synchronized. This Q&A is helpful, but does not answer all of my questions: Java arrays: synchronized + Atomic*, or synchronized suffices? What follows is sample code to demonstrate the issue. Ass…
Keep getting NoClassDefFoundError while loading a class with URLClassLoader
Recently I’m creating something that have to load/unload external jar packages dynamically. I’m now trying to do this with URLClassLoader, but I keep getting NoClassDefFoundError while trying to make new instances. It seems that the external class is loaded successfully since the codes in the cons…
Error when try to persist entity with Hibernate (MappingException: Unknown entity)
I’m using Hibernate 5.0.6 and Hibernate annotations 3.5.6-Final with MySql 5.1.37 in a standalone maven java application. I’m trying to make a simply persistence example work but I receive the following error when I call save: The classes Is pointed via mapping class in the configuration file. But…
How to convert an String Variable with Array to an Integer Variable with Array
I am new to java programming. I am trying to convert an string variable with array to an int variable array but i have 2 errors and have no idea to fix it, any help would be great, thanks.. This is my source code : This is what the errors look like Answer Try below code, it is working.
Getting MainActivity context in CustomView class
I have 2 classes: MainActivity and CustomView. I have an XML layout with this CustomView. I want to access all my MainActivity variables from my CustomView class and also to modify them, I tried to get the context but it didn’t work. MainActivity class: MyCustomView class: I also tried getContext which …
Cannot infer type arguments for ArrayAdapter
I am still playing around with my calendar, I already nearly managed to integrate the https://github.com/SundeepK/CompactCalendarView into one of my fragments. There is just one error left, i did some research, others got the problem too for example with ArrayList<>. Example code: The IDE says: Note: C:…
Android 6.0 multiple permissions
I know that Android 6.0 has new permissions and I know I can call them with something like this Today I saw a Google app which needs 3 permissions: contacts, sms and camera. It’s making a page 1-3 and calls them all together at the same time to activate. Can anybody tell me how I can call 4 permissions …
Space character without “” in properties file keys
I reed properties file: My properties file Key contains space and I need to put character to read it correctly. Is it possible somehow not place character in properties file and read it in correct way? Properties file content: Answer It is possible to load properties from an XML file also… makes for n…
Spark cassandra connector Java API, cannot find symbol CassandraRow
I am trying out the spark-cassandra-connector-japi example from here: https://github.com/datastax/spark-cassandra-connector/blob/master/doc/7_java_api.md The maven build fails with the following error: SimpleApp.java:[24,9] cannot find symbol [ERROR] symbol: class CassandraRow [ERROR] location: class SimpleAp…
High memory usage by gradle daemon
I am using Gradle 2.5 to compile a Java project which consists of 5 modules. In order to speed things up I also use the gradle-daemon. However, During compilation there are up to 18 instances of the gradle-daemon running. After compilation finishes there are still 15 instances of the daemon left. The daemons …