you could either get all the digits out into a list or something, and then parse them back into a number in reverse

or just take the input as a string and reverse the string

can we see more code? for example, what types are all these things? how are they defined?

This line makes no sense; you are getting the value that is associated with the key "info", and then you are testing whether that value is a key in the hash table?

um... where is your code?

so lets look at line 112:
truckinfo[i].Set(inputhp, inputmileage, inputyear);

The two references that you dereference in that line are "truckinfo" and "truckinfo[i]". "truckinfo" isn't null...

do you mean, "it doesn't compile"? there are no classes named Widget, Spork, or Grommet; how do you expect to create new objects of those classes?

yes. (except that in Java the first object is garbage-collected and in C++ it isn't)

you should read a basic guide to Java

Java consists only of primitive types and reference types (which are kind of like pointers in C). Reference types point to objects, and are named after the...

what exactly is your question?

why can't the classes be separate and you just put each class in its own file?

also the "main" method should be static

what is "execution via a webpage"?

if "\" were the separator, you would do
str.split("\\\\")

the reason is that the argument to split() is compiled into a regular expression; and characters which are special in regex need to be...

Scanner.next() returns up to the next delimeter, which is a space by default

what do you expect it to do?

if you want to read the rest of the line, you can use the "nextLine()" method

attribute[] attr=new attribute[no_of_attribute];
attr has no_of_attribute arguments
for(int i=0;i<no_of_entity;i++){
i goes from 0 to no_of_entity
for(int j=0;j<no_of_attribute;j++){
j goes...

there are two lines of
Class.forName ("oracle.jdbc.driver.OracleDriver");
in your code

there are two lines where you call that method; you caught the exception for the second one, but not the first

No, those are local variables inside the method. They do not have access modifiers like "private".