-XX:+UseCompressedClassPointers 允许类指针压缩。 它们默认都是开启的,可以手动关闭它们。 在VM options中输入 -XX:-UseCompressedOops -XX:-UseCompressedClassPointers 1. 2. 再次运行结果如下 9344 Exception in thread "main" java.lang.OutOfMemoryError: Metaspace 1. 2. 表明元空间内存溢出。 jdk1.6 永...
/** use serialVersionUID from JDK 1.0.2 for interoperability */ private static final long serialVersionUID = -6849794470754667710L; ... } 从上面可以看出几点: 1)String类是final类,也即意味着String类不能被继承,并且它的成员方法都默认为final方法。在Java中,被final修饰的类是不允许被继承的,并且该...
privatefinalintoffset; /** The count is the number of characters in the String. */ privatefinalintcount; /** Cache the hash code for the string */ privateinthash;// Default to 0 /** use serialVersionUID from JDK 1.0.2 for interoperability */ privatestaticfinallongserialVersionUID = -6...
Note that use of this constructor is * unnecessary since Strings are immutable. */ public String() { this.value = "".value; this.coder = "".coder; } StringBuffer、StringBuilder 在java.lang.AbstractStringBuilder中: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 /** * Creates an ...
不可变字符串:String。在地址不变的情况下,字符串不可改变 可变字符串:StringBuilder,StringBuffer。地址不变的情况下,想把“ab”变成“abcd”是可能的,直接追加即可sb.append("cd") 区别与联系 String类是不可变类,即一旦一个String对象被创建后,包含在这个对象中的字符序列是不可改变的,直至这个对象销毁。
voidtrimToSize() 尝试减少用于字符序列的存储空间。 声明方法的类 java.lang.Object clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait 声明方法的接口 java.lang.CharSequence chars, codePoints, length, toString构造...
(1)上官方文档,StringBuilder,A mutable sequence of characters. This class provides anAPIcompatible with StringBuffer, but with no guarantee of synchronization. This class is designed for use as a drop-in replacement for StringBuffer in places where the string buffer was being used by a single th...
字符串去重（-XX:+UseStringDeduplication）减少内存占用总结：- `String` 是不可变的字符串类，适用于...
* the same sequence of characters as the argument; in other words, the * newly created string is a copy of the argument string. Unless an * explicit copy of {@codeoriginal} is needed, use of this constructor is * unnecessary since Strings are immutable. ...
Scanner sc = new Scanner(System.in); System.out.println("请输入一个QQ号码"); String qqNum = sc.nextLine(); //校验QQ号的组成规则 // boolean b = checkQQNum(qqNum); boolean b = checkQQNumUseRegex(qqNum); if (b) { System.out.println("QQ规则正确"); ...