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Difference between case object and object
...fined module A
scala> case object B
defined module B
scala> import java.io._
import java.io._
scala> val bos = new ByteArrayOutputStream
bos: java.io.ByteArrayOutputStream =
scala> val oos = new ObjectOutputStream(bos) ...
Java “user.dir” property - what exactly does it mean?
...
It's the directory where java was run from, where you started the JVM. Does not have to be within the user's home directory. It can be anywhere where the user has permission to run java.
So if you cd into /somedir, then run your program, user.dir w...
Access properties file programmatically with Spring?
...have SPEL turned off, one can use this trick:
package com.my.app;
import java.util.Collection;
import java.util.Map;
import java.util.Set;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.conf...
What is the actual use of Class.forName(“oracle.jdbc.driver.OracleDriver”) while connecting to a dat
....driver.OracleDriver");
// and
Class<?> stringClass = Class.forName("java.lang.String");
Class.forName("com.example.some.jdbc.driver") calls show up in legacy code that uses JDBC because that is the legacy way of loading a JDBC driver.
From The Java Tutorial:
In previous versions of JDBC, to...
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...
Why Java needs Serializable interface?
...f this form makes the class internals part of the public API (which is why javadoc gives you the persisted forms of classes).
For long-term persistence, the class must be able to decode this form, which restricts the changes you can make to class design. This breaks encapsulation.
Serialization ca...
Which Java Collection should I use?
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@MattBall I agree with you for the most part. However Java LinkedList is a double linked list, so access at start and at end are both fast. You will note that of the branches above all three questions have to answer yes before I'd recommend using the LinkedList - so in other wor...
Java int to String - Integer.toString(i) vs new Integer(i).toString()
Sometimes java puzzles me.
I have a huge amount of int initializations to make.
11 Answers
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JPA or JDBC, how are they different?
I am learning Java EE and I downloaded the eclipse with glassfish for the same. I saw some examples and also read the Oracle docs to know all about Java EE 5. Connecting to a database was very simple. I opened a dynamic web project, created a session EJB , I used EntityManager and with the get meth...
String isNullOrEmpty in Java? [duplicate]
...d before, but Googling doesn't find it . Is there, in any of the standard java libraries (including apache/google/...), a static isNullOrEmpty() method for Strings ?
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