Java Programming
Basic coding skills
Code identifiers
The rules for naming an identifier
- An identifier is any name that you create in a Java program. These can be the names of classes, methods, variables, and so on.
- Start each identifier with a letter, underscore, or dollar sign. Use letters, dollar signs, underscores, or digits for subsequent characters.
- Use up to 255 characters.
- Don't use Java keywords.
- Remember that Java is a case-sensitive language.
Valid identifiers
| InvoiceApp | $orderTotal | i |
| Invoice | _orderTotal | x |
| InvoiceApp2 | input_string | TITLE |
| subtotal | _get_total | MONTHS_PER_YEAR |
| discountPercent | $_64_Valid |
Keywords
A keyword is a word that's reserved by the Java language. As a result, you can't use keywords as identifiers.
| boolean | if | interface | class | true |
| char | else | package | volatile | false |
| byte | final | switch | while | throws |
| float | private | case | return | native |
| void | protected | break | throw | implements |
| short | public | default | try | import |
| double | static | for | catch | synchronized |
| int | new | continue | finally | const |
| long | this | do | transient | goto |
| abstract | super | extends | instanceof | null |