Long is the Object form of long, and Integer is the object form of int. The long uses 64 bits. The int uses 32 bits, and so can only hold numbers up to ±2 billion (-231 to +231-1). You should use long and int, except where you need to make use of methods inherited from Object, such as hashcode. Java.util.collections methods usually use the boxed (Object-wrapped) versions, because they need to work for any Object, and … Read more
Usually, IllegalStateException is used to indicate that “a method has been invoked at an illegal or inappropriate time.” However, this doesn’t look like a particularly typical use of it. The code you’ve linked to shows that it can be thrown within that code at line 259 – but only after dumping a SQLException to standard output. We can’t tell what’s wrong … Read more
While reading from the file, your are not terminating your loop. So its read all the values and correctly throws EOFException on the next iteration of the read at line below: If you read the documentation, it says: Throws: EOFException – if this input stream reaches the end before reading eight bytes. IOException – the stream has … Read more
I have a Java class. How can I unit test it? In my case, I have class does a binary sum. It takes two byte[] arrays, sums them, and returns a new binary array.
I’m trying to run Cassandra on my computer, but I keep getting the following error message: Anyone know why and how to fix this? I am running: It seems I need to install a 64bit version of JRE. I have tried searching java.com and oracle.com for this, but I can’t find anything obvious which will … Read more
It may not be an easy problem. Determining how to map classes defined in Python into types in Java will be a big challange because of differences in each of type binding time. (duck typing vs. compile time binding).
Just construct a new ArrayList wrapping the keyset of the request parameter map. I only wonder how it’s useful to have it as List<String>. A Set<String> would make much more sense as parameter names are supposed to be unique (a List can contain duplicate elements). A Set<String> is also exactly what the map’s keyset already represents. Or perhaps you don’t need it at all for the particular functional requirement … Read more
I have a new DB2 server (v10.5.0.3), and I can connect to the database locally just fine. When trying to connect from a remote server using JDBC I am getting the “Connection refused. ERRORCODE=-4499, SQLSTATE=08001” error. Based on information found here https://www-304.ibm.com/support/docview.wss?uid=swg21403644 I have confirmed that and with these JDBC connection values I have verified that the … Read more
How to create a sub-array from another array? Is there a method that takes the indexes from the first array such as: I don’t want to go over making loops and making my program suffer. I keep getting error: cannot find symbol method copyOfRange(int[],int,int) This is my code:
I would like to use ant to exectue a command like below: But it replies an error say The ‘ characters around the executable and arguments are not part of the command. The background is: I want to use ant to stop the apache server but it doesn’t installed by the same user I run … Read more