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In which language are the Java compiler and JVM written?
...as developed by Sun Microsystems and was written in C using some libraries from C++. Today, the Java compiler is written in Java, while the JRE is written in C.
We can imagine how the Java compiler was written in Java like this:
The Java compiler is written as a Java program and then compiled wit...
Why does this Java code compile?
...se restrictions are intended to prevent code like
int j = i;
int i = j;
from compiling. The Java spec says "the restrictions above are designed to catch, at compile time, circular or otherwise malformed initializations."
What do these rules actually boil down to?
In short, the rules basically s...
SVN undo delete before commit
If you delete a directory from an SVN working copy, but haven't committed yet, it's not obvious how to get it back. Google even suggests "svn undo delete before commit" as a common query when you type "svn undo d", but the search results are unhelpful.
...
How to declare global variables in Android?
...class and make it available for your entire application. You can access it from any context using the Context.getApplicationContext() method (Activity also provides a method getApplication() which has the exact same effect). Following is an extremely simplified example, with caveats to follow:
clas...
Matplotlib 2 Subplots, 1 Colorbar
...ton's code using the axparameter of figure.colorbar() with a list of axes.
From the documentation:
ax
None | parent axes object(s) from which space for a new colorbar axes will be stolen. If a list of axes is given they will all be resized to make room for the colorbar axes.
imp...
How to create a directory if it doesn't exist using Node.js?
...ou just made a typo in your question?)
The docs explicitly discourage you from using exists.
fs.exists() is an anachronism and exists only for historical reasons. There should almost never be a reason to use it in your own code.
In particular, checking if a file exists before opening it is an anti...
Execute command without keeping it in history [closed]
...h history tips are available here including this method of hiding commands from history
– user379997
Dec 12 '11 at 14:38
...
In Typescript, How to check if a string is Numeric
... longer available in rxjs v6
I'm solved it by using the isNumeric operator from rxjs library (importing rxjs/util/isNumeric
Update
import { isNumeric } from 'rxjs/util/isNumeric';
.
.
.
var val = "5700";
if (isNumeric(val)){
alert("it is number !");
}
...
Check to see if python script is running
... can write a simple shell script to check it for you using the return code from ps.
ps up `cat /tmp/mydaemon.pid ` >/dev/null && echo "Running" || echo "Not running"
For extra credit, you can use the atexit module to ensure that your program cleans up its pidfile under any circumstance...
Difference between ObservableCollection and BindingList
...
An ObservableCollection can be updated from UI exactly like any collection. The true difference is rather straightforward:
ObservableCollection<T> implements INotifyCollectionChanged which provides notification when the collection is changed (you guessed ^^...