Creating thread : error

Question

Hi
class NewThread implements runnable {
Thread t;
NewThread(){
t = new Thread(this, "Demo Thread");
System.out.println("Child Thread:" + t);
t.start();
public void run(){
try{
for(int i =5; i>0; i--){
System.out.println("Child Thread:" + i);
Thread.sleep(500);
catch(InterupptedException e) {
System.out.println("Child interuppted.");
System.out.println("Exiting child Thread);
class ThreadDemo{
new NewThread();
try{
for(i=5; i>0; i--) {
System.out.println("Main Thread:" + i);
Thread.sleep(1000);
}catch(InterupptedException e) {
Sytem.out.println("Main thread interuppted.");
System.out.println("Main thread exiting.");
I AM GETTING THIS ERROR IN COMMAND PROMPT
c:\java>javac ThreadDemo.java
ThreadDemo.java:9: illegal start of expression
public void run(){
^
ThreadDemo.java:9: illegal start of expression
public void run(){
^
ThreadDemo.java:9: ';' expected
public void run(){
^
ThreadDemo.java:15: 'catch' without 'try'
catch(InterupptedException e) {
^
ThreadDemo.java:15: ')' expected
catch(InterupptedException e) {
^
ThreadDemo.java:15: not a statement
catch(InterupptedException e) {
^
ThreadDemo.java:15: ';' expected
catch(InterupptedException e) {
^
ThreadDemo.java:18: unclosed string literal
System.out.println("Exiting child Thread);
^
ThreadDemo.java:18: ';' expected
System.out.println("Exiting child Thread);
^
ThreadDemo.java:10: 'try' without 'catch' or 'finally'
try{
^
ThreadDemo.java:23: illegal start of type
new NewThread();
^
ThreadDemo.java:23: ';' expected
new NewThread();
^
ThreadDemo.java:23: illegal start of type
new NewThread();
^
ThreadDemo.java:23: <identifier> expected
new NewThread();
^
ThreadDemo.java:24: illegal start of type
try{
^
ThreadDemo.java:24: ';' expected
try{
^
ThreadDemo.java:25: illegal start of type
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: <identifier> expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: ';' expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: illegal start of type
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: <identifier> expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: <identifier> expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: illegal start of type
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: <identifier> expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: ';' expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: illegal start of type
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: <identifier> expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: ';' expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:26: <identifier> expected
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: illegal start of type
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: ')' expected
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: ';' expected
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: illegal start of type
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: <identifier> expected
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: ';' expected
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:27: illegal start of type
Thread.sleep(1000);
^
ThreadDemo.java:27: illegal start of type
Thread.sleep(1000);
^
ThreadDemo.java:29: 'catch' without 'try'
}catch(InterupptedException e) {
^
ThreadDemo.java:29: ')' expected
}catch(InterupptedException e) {
^
ThreadDemo.java:29: not a statement
}catch(InterupptedException e) {
^
ThreadDemo.java:29: ';' expected
}catch(InterupptedException e) {
^
41 errors
c:\java>javac ThreadDemo.java
ThreadDemo.java:9: illegal start of expression
public void run(){
^
ThreadDemo.java:9: illegal start of expression
public void run(){
^
ThreadDemo.java:9: ';' expected
public void run(){
^
ThreadDemo.java:15: 'catch' without 'try'
catch(InterupptedException e) {
^
ThreadDemo.java:15: ')' expected
catch(InterupptedException e) {
^
ThreadDemo.java:15: not a statement
catch(InterupptedException e) {
^
ThreadDemo.java:15: ';' expected
catch(InterupptedException e) {
^
ThreadDemo.java:18: unclosed string literal
System.out.println("Exiting child Thread);
^
ThreadDemo.java:18: ';' expected
System.out.println("Exiting child Thread);
^
ThreadDemo.java:10: 'try' without 'catch' or 'finally'
try{
^
ThreadDemo.java:23: illegal start of type
new NewThread();
^
ThreadDemo.java:23: ';' expected
new NewThread();
^
ThreadDemo.java:23: illegal start of type
new NewThread();
^
ThreadDemo.java:23: <identifier> expected
new NewThread();
^
ThreadDemo.java:24: illegal start of type
try{
^
ThreadDemo.java:24: ';' expected
try{
^
ThreadDemo.java:25: illegal start of type
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: <identifier> expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: ';' expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: illegal start of type
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: <identifier> expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: <identifier> expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: illegal start of type
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: <identifier> expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: ';' expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: illegal start of type
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: <identifier> expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:25: ';' expected
for(i=5; i>0; i--) {
^
ThreadDemo.java:26: <identifier> expected
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: illegal start of type
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: ')' expected
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: ';' expected
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: illegal start of type
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: <identifier> expected
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:26: ';' expected
System.out.println("Main Thread:" + i);
^
ThreadDemo.java:27: illegal start of type
Thread.sleep(1000);
^
ThreadDemo.java:27: illegal start of type
Thread.sleep(1000);
^
ThreadDemo.java:29: 'catch' without 'try'
}catch(InterupptedException e) {
^
ThreadDemo.java:29: ')' expected
}catch(InterupptedException e) {
^
ThreadDemo.java:29: not a statement
}catch(InterupptedException e) {
^
ThreadDemo.java:29: ';' expected
}catch(InterupptedException e) {
^
41 errors
c:\java>
Can you please tell me where i am wrong.
Regards,
Neha

Answer 1

NehaVerma wrote:
Hi,
See i am getting this error when i try to run the same program that you wrote after corrections
c:\java>javac ThreadDemo.java
c:\java>java ThreadDemo
Exception in thread "main" java.lang.NoClassDefFoundError: ThreadDemo
Caused by: java.lang.ClassNotFoundException: ThreadDemoIf you don't know how to fix that, then you need to go back to the very basics. Learn the fundamentals before getting anywhere near multithreading.
[Javapedia: Classpath|http://wiki.java.net/bin/view/Javapedia/ClassPath]
[How Classes are Found|http://java.sun.com/j2se/1.5.0/docs/tooldocs/findingclasses.html]
[Setting the class path (Windows)|http://java.sun.com/j2se/1.5.0/docs/tooldocs/windows/classpath.html]
[Setting the class path (Solaris/Linux)|http://java.sun.com/j2se/1.5.0/docs/tooldocs/solaris/classpath.html]
[Understanding the Java ClassLoader|http://www-106.ibm.com/developerworks/edu/j-dw-javaclass-i.html]
java -cp .;<any other directories or jars> YourClassNameYou get a NoClassDefFoundError message because the JVM (Java Virtual Machine) can't find your class. The way to remedy this is to ensure that your class is included in the classpath. The example assumes that you are in the same directory as the class you're trying to run.
javac -classpath .;<any additional jar files or directories> YourClassName.javaYou get a "cannot resolve symbol" message because the compiler can't find your class. The way to remedy this is to ensure that your class is included in the classpath. The example assumes that you are in the same directory as the class you're trying to run.
= = = = = = = = = = = = = =
Sun's [basic Java tutorial|http://java.sun.com/docs/books/tutorial/]
Sun's [New To Java Center|http://java.sun.com/learning/new2java/index.html].Includes an overview of what Java is, instructions for setting up Java, an intro to programming (that includes links to the above tutorial or to parts of it), quizzes, a list of resources, and info on certification and courses.
[http://javaalmanac.com|http://javaalmanac.com]. A couple dozen code examples that supplement [The Java Developers Almanac|http://www.amazon.com/exec/obidos/tg/detail/-/0201752808?v=glance].
jGuru. A general Java resource site. Includes FAQs, forums, courses, more.
JavaRanch. To quote the tagline on their homepage: "a friendly place for Java greenhorns." FAQs, forums (moderated, I believe), sample code, all kinds of goodies for newbies. From what I've heard, they live up to the "friendly" claim.
Bruce Eckel's [Thinking in Java|http://mindview.net/Books/DownloadSites] (Available online.)
Joshua Bloch's [Effective Java|http://www.amazon.com/Effective-Java-2nd-Joshua-Bloch/dp/0321356683/ref=pd_bbs_1?ie=UTF8&s=books&qid=1214349768&sr=8-1]
Bert Bates and Kathy Sierra's [Head First Java|http://www.amazon.com/exec/obidos/tg/detail/-/0596004656?v=glance].
James Gosling's [The Java Programming Language|http://www.bookpool.com/sm/0321349806].