William Hummel's Bookmarks

 7 He holds victory in store for the upright,
       he is a shield to those whose walk is blameless,

 8 for he guards the course of the just
       and protects the way of his faithful ones.

 9 Then you will understand what is right and just
       and fair—every good path.

 2 for attaining wisdom and discipline;
       for understanding words of insight;

 3 for acquiring a disciplined and prudent life,
       doing what is right and just and fair;

 4 for giving prudence to the simple,
       knowledge and discretion to the young-

10 My son, if sinners entice you,
       do not give in to them.

 11 If they say, "Come along with us;
       let's lie in wait for someone's blood,
       let's waylay some harmless soul;

 12 let's swallow them alive, like the grave, ^[b]
       and whole, like those who go down to the pit;

 13 we will get all sorts of valuable things
       and fill our houses with plunder;

 14 throw in your lot with us,
       and we will share a common purse"-

 15 my son, do not go along with them,
       do not set foot on their paths;

 16 for their feet rush into sin,
       they are swift to shed blood.

 17 How useless to spread a net
       in full view of all the birds!

 18 These men lie in wait for their own blood;
       they waylay only themselves!

 19 Such is the end of all who go after ill-gotten gain;
       it takes away the lives of those who get it.

 32 For the waywardness of the simple will kill them,
       and the complacency of fools will destroy them;

 33 but whoever listens to me will live in safety
       and be at ease, without fear of harm."

 6 For the LORD watches over the way of the righteous,
       but the way of the wicked will perish.

According to the syntax rules of Java, a name is a sequence of one or more
characters. It must begin with a letter or underscore and must consist entirely of letters,
digits, and underscores. ("Underscore" refers to the character '_'.) For example, here are some legal
names:

N   n   rate  x15   quite_a_long_name   HelloWorld

No spaces are allowed in identifiers; HelloWorld is a legal identifier,
but "Hello World" is not.
Upper case and lower case letters are considered to be different, so that
HelloWorld, helloworld, HELLOWORLD, and
hElloWorLD are all distinct names.

In Java, the only way to get data into a variable -- that
is, into the box that the variable names -- is with an assignment statement.
An assignment statement takes the
form:

variable = expression;

where expression represents anything that
refers to or computes a data value.

• short corresponds to two bytes (16 bits). Variables of type
  short have values in the range -32768 to 32767.




• 
  int corresponds to four bytes (32 bits). Variables of type
  int have values in the range -2147483648 to 2147483647.




• 
  long corresponds to eight bytes (64 bits). Variables of type
  long have values in the range -9223372036854775808 to
  9223372036854775807.

So, to be a successful programmer, you have to develop a detailed knowledge
of the syntax of the programming language that you are using. However, syntax
is only part of the story. It's not enough to write a program that will
run -- you want a program that will run and produce the correct result! That is, the
meaning of the program has to be right. The meaning of a
program is referred to as its semantics. A
semantically correct program is one that does what you want it to.

Here is a Java program to display the message "Hello World!". Don't expect
to understand what's going on here just yet -- some of it you won't really
understand until a few chapters from now:

// A program to display the message
// "Hello World!" on standard output

public class HelloWorld {
 
   public static void main(String[] args) {
      System.out.println("Hello World!");
   }
      
}   // end of class HelloWorld

The command that actually displays the message is:

System.out.println("Hello World!");

This command is an example of a subroutine call statement.
It uses a "built-in subroutine" named
System.out.println to do the actual work.

Everything else in the program is required by the rules of Java syntax. All
programming in Java is done inside "classes." The first line in the above
program (not counting the comments) says that this is a class named HelloWorld. "HelloWorld," the
name of the class, also serves as the name of the program. Not every class is a
program. In order to define a program, a class must include a subroutine named
main, with a definition that takes the form:

public static void main(String[] args) {
      statements
}

As noted above, a subroutine can't exist by itself. It has to be part of a
"class". A program is defined by a public class that takes the form:

public class program-name {

    optional-variable-declarations-and-subroutines
    
    public static void main(String[] args) {
       statements
    }
    
    optional-variable-declarations-and-subroutines

}