Java Virtual Machine Learning Notes norms
2005-2-25
Java concept
1.Unicode
Java programs prepared by Unicode character encoding.
Unicode character encoding the latest information, see ftp://unicode.org.
Apart from the comments and identifier and character and the content of text strings, Java process all the input elements form only ASCII characters.
2. Identifier identifier (Identifier) is not limited Unicode length of the sequence of letters and numbers, a sequence of characters must be alphabetical.
When transmitted to a Java identifiers are considered the letters or numbers in the Unicode characters, Character.isJavaLetter Java method returns true.
Only two identifiers in their individual letters or numbers with the same characters, Unicode is the same with the same identifier can still shape is different. –> Id case sensitive.
Id not with the Java Boolean keyword or text (true or false) the same.
3. Text Text (literal) is the basic types, String type or types of null value of the source code.
Text string constants, as well as more general expression of the value of the string, the methods used String.intern "internal" to share examples only.
4. Type and value
4.1 The basic types and values is the basic types and numerical types boolean type, numerical type integer and floating-point type.
Integer is byte, short, int, long, respectively, and there are signs that 8,16,32,64 binary complement integer. Integer also char, the value is representative of Unicode characters 16 unsigned integers.
Floating-point type float and double, respectively 32 and 64 IEEE 754 floating-point.
Boolean type is really true and false values.
