1． Int的范围 －214748364――2147483647
2． You can stop a thread indefinitely if you wish to
3． 定义native方法的方式 public native void me();
4． 在静态类中不能引用非静态类变量
5． char=”\u00ee” (right) char=”\U00eee” (wrong)
6． If classA itself can’t be accessed by classB then no member within classA can be accessed by classB
7． If even a single method is abstract,the whole class must be declared abstract.
8． The protected member can be accessed only through inheritance.
9． Local variable only can be declared with final
final变量作为field时，可以在当前行初始化，也可以在构造函数时初始化。
10． Static method can’t be overridden
11． 访问修饰符可以任意调换次序，，但返回类型必须紧贴名称
12． ＋＋I 先＋＋，再赋值，i＋＋，是先赋值，再＋＋
13． HASHMAP 和HASHTABLE的区别：HASHTABLE是线程安全的
14． Main can be declared final
15． Continue must be in a loop
16． Int[][] a={{1,2},{3,4},} (right)
17． System.out.println(4+” ”+2); System.out.println(4+’ ’+2);
a) Int i=10,j=3,k=7,p=30
p+=k-=j4);System.out.println(b); (此时b仍为－1，因为移位时是32位的整数)
a) Int a=28; int b=27 byte t=a-b; compile error
int a=28; int b=27;byte t=0; t+=a-b; (right)
