I keep getting this error when compiling the code . I think its got to do with the Tomcat server not working well with the textpad app...I'm using windows 8.1(for the course I have to use Textpad 4.7.3 & Apache Tomcat 5.5.7 Server) :
C:UsersReignDownloadsIntec - Codecourse technology59850dChapter 12WorkWebStocks.java:20: package javax.servlet does not exist
import javax.servlet.*;
^
C:UsersReignDownloadsIntec - Codecourse technology59850dChapter 12WorkWebStocks.java:21: package javax.servlet.http does not exist
import javax.servlet.http.*;
[code]....
tom cat is running as a service it shows started in the tom cat app and as a running service in windows services !!!
I am using RAD and I copied the Tomcat server from server to local folder. Then I tried to add this tomcat by adding new server. I got the error in title. After searching, I copied the Tomcatconf files to myworkspaceserver omcat at localhost-config, restart RAD and refresh. But now I am getting the error that the conf may corrupted or incomplete.
Currently we are facing a problem in application developed in JSF, Hibernate on Tomcat server 7. The UI is getting freezed after uncertain time. Sometimes it worked for 2 to 5 hours and sometimes it hangs out within 10 mins, too.
Session time out in web.xml is -1
Before, we were getting memory leak logs in catalina, so we implemented ClassLoaderLeakPreventor in the application. When problem occurs, below log is printing in catalina.out.
INFO: Reloading context [/SHRWeb241213] Jan 31, 2014 12:42:36 PM org.apache.catalina.core.StandardContext reload INFO: Reloading Context with name [/SHRWeb241213] has started ClassLoaderLeakPreventor: com.cosmos.leakPrevention.ClassLoaderLeakPreventor shutting down context by removing known leaks (CL: 0x19a37a) ClassLoaderLeakPreventor: Removing 47 classes from Mojarra descriptors cache
"Because X is a compile time constant, the compiler will Y"... But what exactly is a compile time constant? And how can we determine whether something is treated as such?Obviously, a compile time constant is a constant value that is known at compile time... ... Literals are, by definition, compile time constants -- as they are constants, known at compile time.
But the definition of a compile time constant is a bit more complex. To start, let's examine section 15.28 of the Java language specification.A compile-time constant expression is an expression denoting a value of primitive type or a String that is composed using only the following:
Literals of primitive type and literals of type String Casts to primitive types and casts to type StringThe unary operators +, -, ~, and ! (but not ++ or --)The multiplicative operators *, /, and %The additive operators + and - The shift operators <<, >>, and >>>The relational operators <, <=, >, and >= (but not instanceof)The equality operators == and !=The bitwise and logical operators &, ^, and |The conditional-and operator && and the conditional-or operator ||The ternary conditional operator ? : Simple names that refer to final variables whose initializers are constant expressions Qualified names of the form TypeName . Identifier that refer to final variables whose initializers are constant expressions
This is the full definition of a compile time constant. And as you can see, it contains more than just literals. In fact, literals are merely the first bullet point on the list. Also, note that a compile time constant can apply to any literal that is of primative or String type.The next few bullet points are the operations that can be applied to a constant at compile time. This list is actually pretty long, as it is possible to apply most of the operations at compile time. It may actually be easier to remember what can't be apply at compile time -- pre and post increment and decrement, instanceof operator, or any method calls, are not on the list.
The last few bullets are the most interesting. It is possible to use a variable in the expression -- provided that the variable is a compile time constant variable. So... what is a constant variable? Going back to the JLS (section 4.12.4 to be exact)..4.12.4 final Variables.A variable can be declared final. A final variable may only be assigned to once. It is a compile time error if a final variable is assigned to unless it is definitely unassigned (§16) immediately prior to the assignment.
We call a variable, of primitive type or type String, that is final and initialized with a compile-time constant expression (§15.28) a constant variable. Whether a variable is a constant variable or not may have implications with respect to class initialization (§12.4.1), binary compatibility (§13.1, §13.4.9) and definite assignment (§16).The last part of the definition is the relevant part (I still find it amazing that this is that well hidden in the specification). To be a variable that is a compile time constant, the variable needs to be...declared as finalhave a primative or String typeinitialized (on the same line as the declaration)assigned to a compile time constant expression.
I was wondering what happens to the API packages I've imported at compile time. Are they compiled to classes and placed In the same file as the class containing the Import command ?
The reason I'm asking Is because I've noticed the src.zip file Is not In the JRE and since the JRE Is all that's needed to run an app , I'd like to understand what the import command does.
I have a code in which I am reading input from System.in and Destination is some where else
Here is my code
File file=new File("D:/output.txt"); OutputStream os=new java.io.FileOutputStream(file); Scanner scanner=new Scanner(System.in); System.out.println("Enter Data to write on File"); String text=scanner.nextLine(); int c=Integer.parseInt(text); int a; while((a=c.read())!=-1) os.write(a); System.out.println("File Written is Successful");
In the line while((a=c.read())!=-1)
a compile time error is shown "cannot invoke read on primitive data type int"
How can I let Java Web Start download my application from the server every time I run it from the client (without keeping a copy on the client machine) ?
I'm trying to create a server which sends the clients connected to it its local time. Looking at a few tutorials I've managed to connect the clients to the server, but can't send data to the clients. I've successfully done easier examples, without threading. I guess the problem might be im me not knowing what exceptions are for.
Client: When running the code "AAAAAAA" does execute but "BBBB" doesn't, so I guess the problem should be in fraseRecibida = entradaDesdeServidor.readLine();
import java.io.*; import java.net.*; import java.util.Scanner; public class Client { public static void main(String[] args) throws Exception{ String fraseRecibida;
[code]....
I don't understand the exceptions, maybe I should give them a look before continuing with sockets. Being frank I'm not really sure why the while(true) is there.
import java.io.*; import java.net.*; import java.util.Calendar; public class ServerThread extends Thread{ Socket socket; ServerThread(Socket socket){ this.socket = socket;
To deploy my project into %TOMCAT_HOME%webapps folder. Right click on Project ->Export-> War File Project Name: Hello Destination: D:Program FilesApache Software FoundationTomcat 6.0webappsHello.war
Result found in web browser:
HTTP Status 404 - /Hello/first And Hello.war file is not found in webapps folder too after exporting as .war. I am using Apache tomcat 6.0.37, eclipse 3.7.2 release, tomcat plugin :com.sysdeo.eclipse.tomcat_3.3.0
convert or move standalone java thread application into Tomcat server container for accessing its JNDI services? Also is it possible to schedule this thread application in Tomcat server? is it possible to keep this app in tomcat as web application and schedule in window's scheduler.
I'v tried everything, i'v tried to create new path in enviornment variables i tried adding this path -->(C:Program FilesJavajdk1.8.0_20bin) to the end of the default path doesnt work i uninstalled and reinstalled and did the same thing over and it didnt work am i editing the files wrong ? what i do is write the hello world program in eclipse to make sure there arent any errors then copy and paste in note pad++ save it as a .java file and it doesnt work i tried save it in regular notepad as .java laso and it doesnt work iv done every thing i could possibly find on youtube is this stuff outdated ? is there a new way? this one one of the errors ill get
C:javat>javac helloworld.java helloworld.java:1: error: '{' exp public class helloworld.java { ^
And this is the code for that file im trying to compile
public class helloworld.java { public static void main (String args[]){ System.out.println("hello world"); } }
I am totally new to programming in every way, shape or form, and I'm working my way through the Head First Java book (2nd ed). I have just finished copying the code for the initial BeatBox app, the one starting on page 420. When I try to compile it, I get these errors:
BeatBox.java:36: cannot find symbol symbol : constructor Box(int) location: class Box Box buttonBox = new Box(BoxLayout.Y_AXIS); ^ BeatBox.java:40: cannot find symbol symbol : method add(javax.swing.JButton) location: class Box buttonBox.add(start);
[code]....
I doubt that this is relevant, but I'm running Mac OS X, coding in TextWrangler and compiling with Terminal. Java version is 1.6.0_24.
Why can't I see the text when I compile the java code?
Java Code:
import java.io.*; import java.util.logging.Level; import java.util.logging.Logger; import javax.imageio.ImageIO; import javax.swing.*; public class WorldTravel { public static void main (String[] args){ JFrame f = new JFrame("World Travel!"); BG_text p = new BG_text();
I am looking for a way to compile Java Source-Files at runtime and save them all in an executable jar; almost like an IDE would do. I know that there is the javax.tools package which provides a JavaCompiler interface and you can use ToolProvider.getSystemJavaCompiler() to get an instance of a compiler. However, this method has one important problem: it only works on machines that have the JDK installed. Not when only the JRE is installed.
I guess at this point that I need some kind of third party library that offers an implementation of a JavaCompiler. Unfortunately, this is really complicated to search for on the internet since all top listings when searching "compile java at runtime jre" do not really provide a solution to the problem.
I am writing a (somewhat) complex simulation software right now which is supposed to be used by people who have absolutely no knowledge of programming. At the same time, this software should provide the user with a certain amount of flexibility and control over the flow of the simulation.
My previous take on this problem was to build a complex system to interprete user settings from a GUI. I would basically read the GUI input, output it to some kind of own scripting syntax which I just quickly made up and have that interpreted at runtime. Then I realized, that is a silly concept and I threw it out before I got far into the developement. The much better solution I came up with is taking the input from the GUI, create java source code from it and compile it at run-time. Seems much cleaner and nicer to me; will also probably have a better performance, but thats not really an issue anyways.
In reference to the book "Head First Servlets and JSP, 2nd edition", chapter-3(), page-81, the command to compile the servlet file to the desired location is
(from the same directory as can be confirmed from the attachment of screenshot of error). this code is in accordance to the location of the respective files in my system, in particular the servlet-api.jar file.
After doing this, my computer is showing the error : file not found.
How do I resolve this? Actually, I don't understand completely what this code is trying to accomplish.
I'm having problems with the public static void main(String args[]) part. Everything else is correct before this, my teacher has checked that. I have been trying to research why it won't compile right and can't find any errors.
/* Chapter 6:Telephone Purpose:This project displays a telephone keypad you can use to type in a phone number. */ import java.awt.*; import java.datatransfer.*; import java.awt.event.*; import javax.swing.JOptionPane; public class Telephone extends Frame implements ActionListener
I am trying to compile multiple jar files into one jar file from inside a java program. I know how to do this with shell scripts but I would rather have a universal application than one that will only run on Mac, Windows, or Linux. This is my current compiler code:
if(System.getProperty() == "Mac OS X"){ Runtime.getRuntime().exec("javac -classpath jar1.jar; jar2.jar"); }
I would then continue this on for Linux and Windows, but this limits my application.
class SubB{ public void foo(){ System.out.println(" x"); } } public class X extends SubB { public void foo() throws RuntimeException{ super.foo(); if(true) throw new RuntimeException(); System.out.println(" B"); } public static void main(String [] args){ new X().foo(); } }
Why the foo method of class X is not throwing a compile error because according to the override rule, if the superclass method has not declared exception, the subclass method can't declare a new exception...
I moved some static html pages I was hosting from apache into tomcat. (no point in running two servers) This works as expected, but I'm having trouble with the authentication part. In apache the authentication was handled by htaccess. I tried various tutorials on the web about configuring basic authentication in tomcat using WEB-INF/web.xml in tomcat, but I'm not sure this approach applies to static html pages. Using basic authentication for static html in tomcat?
I am trying to make a simple login using netbeans, derby database included in netbeans and tomcat server. I made everything nice and separated: I have a model package with a class called DbConnector that has the following method:
Then i have another class, an userDAODB that has a password check method:
public boolean checkPassword(String user, String password) { try (Connection con = new DbConnector().connect(); Statement stmt = con.createStatement()) { //checks the password in the database
In the main method of this class i tested everything, it works very nice, logs me in, other methods work too, no problem what so ever.But then i go to my servlet:
public class LoginTest extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String username = request.getParameter("username"); String pass = request.getParameter("pass"); UserDAODB userDAO = new UserDAODB(); boolean authe = userDAO.checkPassword(username, pass);
[code]....
So when i start the webpage and i try to click on the login button I get a NullPointerException com.model. UserDAODB. check Password (User DAODB. java:14) - so line 2 here
I have been googling a bit, i placed the derby.jar and the derbyclient.jar in the lib directory of tomcat, i tried to modify the context.xml of my application, but then it wouldn't even start anymore.
It works in the first time. But, after sometime the data is not retrieved and display empty screen. Once, i stop and start the server again, the data is getting retrieved again. But, later when we refresh the empty page is getting displayed again.
