Java Reference
In-Depth Information
javac: Illegal Start of Expression
This is a generic error message if we didn't tidy up an expression as we should
have and the compiler isn't ready to start a new expression yet—for instance,
if I leave off the closing brace at the end of a function:
public void
disable() {
log.info(
"Stopping."
);
Again I'll get a bunch of errors, starting at the point of the missing brace and
continuing way past it into the rest of the file:
src/helloworld/HelloWorld.java:21: illegal start of expression
public void
helloCommand(MessageReceiver caller,
String[]
parameters)
^
src/helloworld/HelloWorld.java:21:
';'
expected
public void
helloCommand(MessageReceiver caller,
String[]
parameters)
^
src/helloworld/HelloWorld.java:21:
';'
expected
public void
helloCommand(MessageReceiver caller,
String[]
parameters)
^
src/helloworld/HelloWorld.java:21: not a statement
Just remember that “illegal start” really means “didn't finish properly.”
javac: Class Is Public, Should Be Declared in a File Named…
In my
HelloWorld.java
, I get creative and start to add another class declaration
at the end of the file:
public class
TooMany {
// ...
}
This generates a very descriptive error message:
src/helloworld/HelloWorld.java:32:
class
TooMany is
public
,
should be declared in a file named TooMany.java
public class
TooMany {
Remember that every public class must be in a separate file that is named
for the class, in a directory named for the package.
However, you
can
declare a
private
class inside your public class within the
same file. This can sometimes be helpful for small helper classes.
