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What is the difference between “instantiated” and “initialized”?
...hem a valid value if you do not do so explicitly. int's initialize to zero by default, DateTime's initialize to DateTime.MinValue by default.
Reference type variables initialize to the object you give it. The compiler will not assign an object (i.e. a valid value) if you don't. In this case the val...
Difference between save and saveAndFlush in Spring data jpa
I am trying to learn spring data JPA by testing some CRUD operation via JpaRepository .
2 Answers
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Database cluster and load balancing
...all a cluster a set of replicated servers.
Replication defines the method by which a set of servers remain synchronized without having to share the storage being able to be geographically disperse, there are two main ways of going about it:
master-master (or multi-master) replication: Any server ...
What can you use Python generator functions for?
...
Generators give you lazy evaluation. You use them by iterating over them, either explicitly with 'for' or implicitly by passing it to any function or construct that iterates. You can think of generators as returning multiple items, as if they return a list, but instead of re...
How to correctly use the extern keyword in C
...lt;stdio.h>
Code...
Now if both myCFile1.o and MyCFile2.o are linked by the linker they will both point to the same errno. Thus, solving the implementation with extern.
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How do I turn on SQL debug logging for ActiveRecord in RSpec tests?
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By default, all your db queries will be logged already in test mode. They'll be in log/test.log.
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How to hide action bar before activity is created, and then show it again?
...tionBar but then, as you say, getActionBar(); returns null.
This is solved by:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
getActionBar().hide();
setContentView(R.layout.splash); // be ...
Closing WebSocket correctly (HTML5, Javascript)
...t):
To close the connection cleanly, a frame consisting of just a 0xFF byte
followed by a 0x00 byte is sent from one peer to ask that the other peer
close the connection.
If you are writing a server, you should make sure to send a close frame when the server closes a client connect...
How to fix “Headers already sent” error in PHP
...be:
Unintentional:
Whitespace before <?php or after ?>
The UTF-8 Byte Order Mark specifically
Previous error messages or notices
Intentional:
print, echo and other functions producing output
Raw <html> sections prior <?php code.
Why does it happen?
To understand why h...
Array slicing in Ruby: explanation for illogical behaviour (taken from Rubykoans.com)
I was going through the exercises in Ruby Koans and I was struck by the following Ruby quirk that I found really unexplainable:
...