The errors explain themselves.
simple.java:4: class Simple is public, should be declared in a file named Simple.java
...your class should be declared in a file named Simple.java
Public classes in Java need to be in a file by the same name.
simple.java:2: package javax.servlet does not exist
javax.servlet doesn't exist. Note that it is part of the enterprise edition (J2EE), rather than the standard edition. You need to have the right distribution installed in order to use these features.
The "cannot find symbol" errors are a simple consequence of the imaginary javax.servlet package. When that problem is corrected, the compiler will know where to find them