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What is static nested class and usage in Java

Question -What is static nested class and usage in Java

Solutions– Many developers are confused and telling static nested class as static inner class.But in java, there is no static inner class. 😮

Ok.First we understand ,

what is inner class – inner class or nested class is a class declared entirely within the body of another class or interface.An instance of a normal or top-level class can exist on its own. By contrast, an instance of an inner class cannot be instantiated without being bound to a top-level class.

class OuterClass {

  class InnerClass {  }

}

Types of nested classes in Java

Member class – They are declared outside a function (hence a “member”) and not declared “static”.
Local class
Anonymous class

Nested or inner class is a member of its enclosing class.
Non-static nested classes (inner classes) have access to other members of the enclosing class, even if they are declared private. Static nested classes do not have access to other members of the enclosing class.A static nested class interacts with the instance members of its outer class (and other classes) just like any other top-level class. In effect, a static nested class is behaviorally a top-level class that has been nested in another top-level class for packaging convenience.

Why we use– if a class does’nt depend on anything other than his outer class then we will create static nested class.for example – we have nThere is no need for LinkedList.Entry to be top-level class as it is only used by LinkedList (there are some other interfaces that also have static nested classes named Entry, such as Map.Entry – same concept). And since it does not need access to LinkedList’s members, it makes sense for it to be static – it’s a much cleaner approach.

Happy learning with Vinay in techartifact…

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How to Read/convert an InputStream to a String

There are multiple ways .I will list down few of them.

Using Old and standard java solution –

public static String fromStream(InputStream in) throws IOException
{
    BufferedReader reader = new BufferedReader(new InputStreamReader(in));
    StringBuilder out = new StringBuilder();
    String line;
    while ((line = reader.readLine()) != null) {
        out.append(line);
    }
    return out.toString();
}

return sb.toString();

if you using Google-Collections/Guava-

InputStream stream = ...
String content = CharStreams.toString(new InputStreamReader(stream, Charsets.UTF_8));
Closeables.closeQuietly(stream);

If you can use Apache Common library..then this is useful –

StringWriter writer = new StringWriter();
IOUtils.copy(inputStream, writer, encoding);
String theString = writer.toString();

Quick way but only work in deserialization process –

String result = (String)new ObjectInputStream( inputStream ).readObject();

Note:ObjectInputStream is about deserialization, and the stream have to respect the serialization protocol to work, which may not always true in all cases.

In the end, the most efficient solution and only in two lines using java Scanner class –

Tricky is to remember the regex \A, which matches the beginning of input. This effectively tells Scanner to tokenize the entire stream, from beginning to (illogical) next beginning.

public static String convertToString(InputStream in) {
    java.util.Scanner s = new java.util.Scanner(in).useDelimiter("\\A");  
        
    return s.hasNext() ? s.next() : "";
}

I would love to hear any comment by you for making more simple…

Happy learning by Vinay Kumar in techartifact

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Get intradoc Server port in custom component in Webcenter Content (UCM)

Requirement – How to get intradoc server port in custom component in Webcenter Content.

Solution – We can use one class called sharedObject which give us environment value.One of my friend(Jonathan) helped me in this.

use SharedObjects.getEnvironmentValue(“IntradocServerPort”) will give you intraDocServer port.

SharedObjects.getEnvironmentValue("IntradocServerPort");

Read more on http://jonathanhult.com/intradoc-api/intradoc/shared/SharedObjects.html

Quick tip in end of weekend
Happy coding with Vinay Kumar in Techartifact.