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Is there a performance difference between a for loop and a for-each loop?
...
From Item 46 in Effective Java by Joshua Bloch :
The for-each loop, introduced in
release 1.5, gets rid of the clutter
and the opportunity for error by
hiding the iterator or index variable
completely. The resulting idiom
applies equally...
Difference between wait() and sleep()
...it of missing information. Many people wrote down the definitions from the Javadoc and also the meaning of the two english words but I do not see Why I should ever use sleep instead of wait? What is the benchmarking and speed difference between the two? If I can do everything that I can do with sle...
Difference between Inheritance and Composition
...same?
If I want to implement the composition pattern, how can I do that in Java?
17 Answers
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How to reference constants in EL?
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EL 3.0 or newer
If you're already on Java EE 7 / EL 3.0, then the @page import will also import class constants in EL scope.
<%@ page import="com.example.YourConstants" %>
This will under the covers be imported via ImportHandler#importClass() and be ava...
How to extract a substring using regex
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import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Test {
public static void main(String[] args) {
Pattern pattern = Pattern.compile(".*'([^']*)'.*");
String mydata = "some string with ...
Getting all names in an enum as a String[]
...ream(e.getEnumConstants()).map(Enum::name).toArray(String[]::new);
}
Pre Java 8 is still a one-liner, albeit less elegant:
public static String[] getNames(Class<? extends Enum<?>> e) {
return Arrays.toString(e.getEnumConstants()).replaceAll("^.|.$", "").split(", ");
}
That you w...
How do you remove a Cookie in a Java Servlet
How do you remove a cookie in a Java servlet?
6 Answers
6
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How to put Google Maps V2 on a Fragment using ViewPager
...ut_height="match_parent" />
</RelativeLayout>
Now, we code the Java class for showing the map in the file MapViewFragment.java:
public class MapViewFragment extends Fragment {
MapView mMapView;
private GoogleMap googleMap;
@Override
public View onCreateView(LayoutInfla...
Does setting Java objects to null do anything anymore?
I was browsing some old books and found a copy of "Practical Java" by Peter Hagger. In the performance section, there is a recommendation to set object references to null when no longer needed.
...
Difference between an application server and a servlet container?
...rvlet API (including JSP, JSTL).
An application server supports the whole JavaEE - EJB, JMS, CDI, JTA, the servlet API (including JSP, JSTL), etc.
It is possible to run most of the JavaEE technologies on a servlet-container, but you have to install a standalone implementation of the particular tec...