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What's the best way to build a string of delimited items in Java?
While working in a Java app, I recently needed to assemble a comma-delimited list of values to pass to another web service without knowing how many elements there would be in advance. The best I could come up with off the top of my head was something like this:
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java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
I'm using the support library for my app. In my FragmentActivity I'm using an AsyncTask for downloading data from internet. In the onPreExecute() method I add a Fragment and in the onPostExecute() method I remove it again. When the orientation is changed in between, I get the above mentioned excepti...
What is the Java string pool and how is “s” different from new String(“s”)? [duplicate]
...allows string constants to be reused, which is possible because strings in Java are immutable. If you repeat the same string constant all over the place in your Java code, you can actually have only one copy of that string in your system, which is one of the advantages of this mechanism.
When you u...
Detecting Windows or Linux? [duplicate]
I am seeking to run a common Java program in both Windows and Linux.
5 Answers
5
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Why do people still use primitive types in Java?
Since Java 5, we've had boxing/unboxing of primitive types so that int is wrapped to be java.lang.Integer , and so and and so forth.
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How do we count rows using older versions of Hibernate (~2009)?
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In Java i usually need to return int and use this form:
int count = ((Long)getSession().createQuery("select count(*) from Book").uniqueResult()).intValue();
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What actually causes a Stack Overflow error? [duplicate]
... everywhere and can't find a solid answer. According to the documentation, Java throws a java.lang.StackOverflowError error under the following circumstance:
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Consistency of hashCode() on a Java string
The hashCode value of a Java String is computed as ( String.hashCode() ):
8 Answers
8
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Getting the error “Java.lang.IllegalStateException Activity has been destroyed” when using tabs with
I have an application that consists of using ActionBarSherlock in tab mode.I have 5 tabs and the content of each tab is handled using fragments. For tab2 though, I have a fragment the xml file of which holds a ViewPager element which in turn has some fragment pages. When I initially start the applic...
How do I programmatically determine operating system in Java?
I would like to determine the operating system of the host that my Java program is running programmatically (for example: I would like to be able to load different properties based on whether I am on a Windows or Unix platform). What is the safest way to do this with 100% reliability?
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