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Can searchResponse.getHits().getHits(); throw nullpointer exception

We are getting a nullpointerexception at searchResponse.getHits().getHits();
I'm totally new to elastic search and don't know how it works but need to analyse this issue.
Let me know if it throws nullpointerexception in any case ?
If it throws how to handle this ?

Looking at the code of InternalSearchResponse, it looks like hits gets initialised with SearchHits.empty() even if the response is empty.
For the other cases, it always gets initialised with new. You can have a look at the source code here.

I had the same exception after an update from 7.4 to 7.17.
It seems that the hits variable of the internalResponse can be NULL, at least in 7.17.1 - could be related to HL request option ignoreUnavailable set to FALSE, and/or queering a no longer existing index.
searchResponse.getHits() can return NULL!

Why am i getting ConcurrentModificationException on this unmodifiableSet?

I'm getting a java.util.ConcurrentModificationException on the line where the for-loop starts (see comment in code).
Why am i getting ConcurrentModificationException on this unmodifiableSet?
final Set<Port> portSet = Collections.unmodifiableSet(node.getOpenPorts());
if (!portSet.isEmpty()) {
StringBuilder tmpSb = new StringBuilder();
for (Port pp : portSet) { // <------- exception happening here
tmpSb.append(pp.getNum()).append(" ");
}
}
I've never witnessed this, but I'm getting crash reports from Google.

Something must be modifying the underlying set; i.e. the set returned by node.getOpenPorts().
Instead of wrapping the set with an "unmodifiable" wrapper, you could copy it.
final Set<Port> portSet = new HashSet<>(node.getOpenPorts());
But as a commenter (#Slaw) pointed out, that just moves the iteration inside the constructor and you would still get CCMEs.
The only real solutions are:
Change the implementation of the node class to use a concurrent set class for the port list that won't throw CCMEs if the collection is mutated while you are iterating it.
Change the implementation of the node class to return a copy of the port list. Deal with the updates-while-copying race condition with some internal locking.
Put a try / catch around the code and repeat the operation if you get a CCME
I've never witnessed this, but I'm getting crash reports from Google.
Yes. The problem only occurs if this code is executed while the open port list is changing.

How to convert inputrstream or string to Exception?

I tried to execute jar from Java code with:
Runtime.getRuntime.exec("java -jar a.jar")
I could get InputStream with error from Process.getErrorStream().
Can I take this stream and if it has an Exception transform it to Exception and throw in my upper application?
Has Java some mechanism to convert string to Exception?
EDIT: Or maybe java has some mechanism like System.exit(int code) but with Exception? So in parent app I can do something like process.waitFor() but take an exception instead int code?

Process.getErrorStream() returns an IntputStream connected to the error output of the subprocess.
So, it is not exception in Java terms. It's an output information which must be considered as an error detected by the process during its execution.
Java don't convert automatically InputStream or String to Exception.
So, you could read this stream in a String and throw a custom exception with as message the string.
If you want that the caller may be able to handle this exception in a clean way, don't use a RuntimeException but a checked exception :
public class ProcessExecutionException extends Exception{
public ProcessExecutionException(String errorOutputMsg){
super(errorOutputMsg);
}
}
Edit for answering your comment :
Yeah, but how to check is inputstream line is a part of stacktrace of
child exception
it's not a stracktrace but error messages as explained.
and how much line from IS i should add to ProcessExecutionException?`
You have to read all the errorStream until it returns null if you want to capture all error output.
In my case my jar is a Spring Application and it write to error stream
nor only Exception that i really need to catch, also some information
like "Error, you have no sl4j xml file, etc - like example". And i
need only really important exception
How the classes producing errors in output may guess if it is important for you or not ?
You must decide yourself which error message pattern should be considered as an important error or not.
Personally, if when my process is run, I have a not well configured logger, I will kill it and correct this problem before starting it again.
If you have input in the ErroStream, you can also inspect the value of the Process.exitCode() (0: normal termination, else problem).
If it is different from 0, you can suspect that it not only a little problem.
Here, some tracks to try.
Can i return something to exit like in System.exit()
In the child process, you can try to intercept all exceptions not handled which may be triggered . You can do it whatever the way (aspect, global try/catch, filter...) .
In this way, if you intercept an exception not handled and that you consider that the application must be terminated, you can do a System.exit with the expected code by the parent process.
In this way, in the parent, if Process.exitCode() matchs with expected code for important exception, you can handle it as you wish.

ConcurrentModificationException crashes my app

My Android app has an IntentService where it requests a list of MessageThreads objects from Facebook, parses the JSON response to build an ArrayList of the objects:
ArrayList<MessageThread> mMessageThreads = new ArrayList<MessageThread>();
Then it calls FB again in the same service, get the names for the MessageThread ids and matches them with the MessageThread objects. At this point I have an ArrayList with complete MessageThread objects and I insert them into an SQLite db.
// save to db and broadcast
for (MessageThread message : mMessageThreads) {
((FBClientApplication)getApplication()).getMessagesData().insertOrIgnore(message.toContentValues();
}
where:
public void insertOrIgnore(ContentValues values) {
SQLiteDatabase db = this.dbHelper.getWritableDatabase();
db.insertWithOnConflict(TABLE, null, values, SQLiteDatabase.CONFLICT_IGNORE);
}
Via ACRA reports I see that intermittently the line
for (MessageThread message : mMessageThreads)
throws an ConcurrentModificationException and the app forcloses. I haven't been able to isolate under what conditions. I read about this Exception and as I understand it it happens when we remove items from an ArrayList while iterating over it, but I'm not removing items from the list. Any pointers to help with this problem are greatly appreciated.

It also happens when you add items to an ArrayList while iterating over it, which it looks like you might do in this code.
In general, it's any "structural modification" that occurs to the ArrayList that can cause a CME while iterating.

What you can try to do is when you iterates your Collection instead of using the original you can make a copy right there, so you will have something like:
for (MessageThread message : new List<MessageThread>(mMessageThreads))
That will help you to avoid CuncurrentModificationException.
Now if you really want to get fancy you can protect your code using synchronized blocks such as:
synchronized(mMessageThreads){
for (MessageThread message : new List<MessageThread>(mMessageThreads)){
...
}
With this last pice of code you will restrict the access to mMessageThreads, if somebody it's using it it will get locked, so if somebody else wants to use it needs to wait until the first one is done.

can't find file... using eclipse and file/filereader/bufferedreader

http://pastebin.com/m5fa7685e
It seems to fail when getting f3.. Output is:
not ready
File is null
Exception in thread "main" java.lang.NullPointerException
at BuabFile.parseBUAB(BuabFile.java:93)
at AddressBook.createBrowseForm(AddressBook.java:232)
at AddressBook.(AddressBook.java:51)
at Main.main(Main.java:4)"
But not before then - no file not found errors or anything...

My guess would be that the parseBUAB() method receives a "null" argument. Which means that it could be that it is the AddressBook class is responsible for the error.

It looks like you forgot to assign a value to BuabFile.file static field. You may want to add this to the end of your readFile() method:
BuabFile.file = f3;
I am guessing your AddressBook.createBrowseForm method looks something like this:
String filename = ...;
BuabFile buab = new BuabFile(filename);
buab.readFile();
ArrayList<String> buabLines = buab.returnFile(); // Returns null because readFile() never assigned a value to BuabFile.file
ArrayList<Buab> buabList = buab.parseBUAB(buabLines);

From all I can see, you just call parseBUAB(..) with a null value. I can't see the call to that method so you have to check the rest of your code.
For your 'not ready' output, which is created because your BufferedReader f3 is 'not ready', the API says
True if the next read() is guaranteed not to block for input, false otherwise.
Maybe you just call it too fast and the file is not loaded yet. Play with Thread.sleep() before calling ready() on the stream. Maybe a some-milliseconds blocking is just normal for File I/O.
And third - if f3 is the BufferedReader you want to keep, you have to assign it to the member file in the readFile() method. But now that's all I found ;)

I'm confused further but have found an answer sort of - I'm using windows 7 and have tried it on a windows xp computer and the code compiles fine and reads in the file (other errors you lot have noted are to be changed anyway through development - this was just one stick in the way...).
I'm wondering if there is some Windows 7 error with eclipse and opening/reading files...