Harshit Rastogi

Paul Clapham wrote:Or, to put it more simply, the file is in the root directory of the jar? Then...
getClass().getResourceAsStream("/file.txt")

yes it worked. the file is already in the root. thnx

I have following structure in jar

myjar.jar -> com -> MYProgram.class
-> file.txt

The file.txt is inside the myjarar.jar and parallel to com folder..
In MYProgram i am trying to do:

getClass().getResourceAsStream("../file.txt")
I am getting NullpointerException when i try to read the inputstream..

Where is it going wrong ?

Objects created by new operator and global variables are stored in heap..

All local variables created inside methods are stored in stack...

Advantage of using enum:

1) can you in the switch case
2) can use the properties of an Enum class like using constructor etc
3) no need to implement the enum. can be used as an other class imported.

Prefer Enum only when all the constants belong to same category,. like No of days, Currencies etc.

while overriding the method the scope/access of the method cannot be more restricted.

For eg, in your case the protected method can be overriden with public and protected modfier. if you put private, compile time error will be there

similarily public method cannot become protected ...

Check out the question 4,5 & 6 . I hope this would help
Abstract class and interface

private ArrayList<Activity> Priority4 = new ArrayList<Activity>();

Change this to
private [b]List[/b]<Activity> Priority4 = new ArrayList<Activity>();

you should always use the interface class . Thats a good practice. Because if in case you want to change it to Vector simply change the implementation

This link might help you:
Difference

The second line is giving false because you have overloaded the equals method and not overriden, so in 2nd case the Object class equals method is called.

change your equals method to

public boolean eqauls(Object f ){ Q f = (Q) f; // procees now }

Hi
please see the following code.

String s = "Monday"; if(s.subString(0,3).equals("Mon"){} String s2 = new String(s.subString(0,3)); String s3 = s.subString(0,3);

I know that line 3 will still point to "Monday" and have a new String object with the offset and count set to 0,3.
The line 5 will create a new String "Mon" in string pool and point to it.
But not sure what about line 6 whether it will behave like line 3 or line 5.

If i am wrong for line 2 or 4 also please correct..
Thanks

i think it will depend on the available meomry in heap of JVM...

Hi ,

First question why do you need vector. IF your application is not multithreaded use arraylist.You can put an arraylist or array in an Arraylist .

List list = new ArrayList(); for{}{ List newList = new ArrayList(); newList.add(arg0); newList.add(arg0); // the values you want to add newList.add(arg0); list.add(newList); }

I would recommend instead of using newList object create a Car class with all the properties in it . save the data in Car object and add it to the list.

Static methods are typically used for utility classes. Consider Math class though the class is final but all methods are static and doesnt needs an instance to access methods. If in case it had not been I can extend Math class and shadow or hide the method of Math class and implement mine in the custom class.

Overriding is done for instance methods and you can take any example in real world...
Like
class Animal{} class Dog extends Animal{}

you can go through this link also :Use of hashcode and equals

Panumat Wiwatmaikul wrote:
At this time, &quot;abc&quot; and &quot;def&quot; will be eligible to GC.

Correct me if i misunderstood.

the String object are not eligible for GC. String "abc" is created in a heap but it has a reference in the String pool which is used by the String objects. But is string object is set to null, still a reference is present in string pool for further reference by an other variable.
Check this javaranch link on Strings :String literal