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JPA EntityManager: Why use persist() over merge()?
...ed (any changes you make will not be part of the transaction - unless you call merge again). You can through use returned instance (managed one).
Maybe a code example will help.
MyEntity e = new MyEntity();
// scenario 1
// tran starts
em.persist(e);
e.setSomeField(someValue);
// tran ends, an...
Can JSON start with “[”?
From what I can read on json.org , all JSON strings should start with { (curly brace), and [ characters (square brackets) represent an array element in JSON.
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How to Copy Contents of One Canvas to Another Canvas Locally
I'd like to copy ALL contents of one canvas and transfer them to another all on the client-side. I would think that I would use the canvas.toDataURL() and context.drawImage() method to implement this but I am running into a few issues.
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Choosing between MEF and MAF (System.AddIn)
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one small thing: please remember that 'separate appdomain' does NOT help you if your addon crashes in a native layer, for that you will still need worker processes. MAF helps somewhat with creating them, but dynamically recovering ...
Print the contents of a DIV
...rs later, this will produce "a.browser is undefined" because the .browser call has been removed in jquery 1.9
– KingsInnerSoul
Aug 24 '18 at 20:58
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Easy way of running the same junit test over and over?
...for some simple way to run JUnit 4.x tests several times in a row automatically using Eclipse.
12 Answers
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Ruby on Rails: how do I sort with two columns using ActiveRecord?
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Assuming you're using MySQL,
Model.all(:order => 'DATE(updated_at), price')
Note the distinction from the other answers. The updated_at column will be a full timestamp, so if you want to sort based on the day it was updated, you need to use a function to ...
HashMap and int as key
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You can't use a primitive because HashMap use object internally for the key. So you can only use an object that inherits from Object (that is any object).
That is the function put() in HashMap and as you can see it uses Object for K:
public V put(K key, V value) {
if (key == nu...
Android Fragments: When to use hide/show or add/remove/replace?
...n detached from the window so it's no longer visible. So you could technically still interact with the fragment and reattach its UI later you need to. If you replace the fragment, the you are actually pulling it out of the container and it will go through all of the teardown events in the lifecycl...
Unable to launch the IIS Express Web server, Failed to register URL, Access is denied
...of the task bar and right-click the IIS Express icon. This will pop up a small window showing you the web sites that IIS Express is currently running...
If you click on one of the items under "View Sites" you have the option to stop that site. Or, you can click the Exit item at the bottom of the ...