Java 注释

• 方法注释

    /**
     * Returns <tt>true</tt> if, and only if, {@link #length()} is <tt>0</tt>.
     *
     * @return <tt>true</tt> if {@link #length()} is <tt>0</tt>, otherwise
     * <tt>false</tt>
     *
     * @since 1.6
     */
    public boolean isEmpty() {
        return value.length == 0;
    }

• 字段/属性注释

    /** The value is used for character storage. */
    private final char value[];

    /** Cache the hash code for the string */
    private int hash; // Default to 0

    /** use serialVersionUID from JDK 1.0.2 for interoperability */
    private static final long serialVersionUID = -6849794470754667710L;

    /**
     * Class String is special cased within the Serialization Stream Protocol.
     *
     * A String instance is written initially into an ObjectOutputStream in the
     * following format:
     * <pre>
     *      <code>TC_STRING</code> (utf String)
     * </pre>
     * The String is written by method <code>DataOutput.writeUTF</code>.
     * A new handle is generated to  refer to all future references to the
     * string instance within the stream.
     */
    private static final ObjectStreamField[] serialPersistentFields =
            new ObjectStreamField[0];

• 方法内注释

    public boolean regionMatches(boolean ignoreCase, int toffset,
            String other, int ooffset, int len) {
        char ta[] = value;
        int to = toffset;
        char pa[] = other.value;
        int po = ooffset;
        // Note: toffset, ooffset, or len might be near -1>>>1.
        if ((ooffset < 0) || (toffset < 0)
                || (toffset > (long)value.length - len)
                || (ooffset > (long)other.value.length - len)) {
            return false;
        }
        while (len-- > 0) {
            char c1 = ta[to++];
            char c2 = pa[po++];
            if (c1 == c2) {
                continue;
            }
            if (ignoreCase) {
                // If characters don‘t match but case may be ignored,
                // try converting both characters to uppercase.
                // If the results match, then the comparison scan should
                // continue.
                char u1 = Character.toUpperCase(c1);
                char u2 = Character.toUpperCase(c2);
                if (u1 == u2) {
                    continue;
                }
                // Unfortunately, conversion to uppercase does not work properly
                // for the Georgian alphabet, which has strange rules about case
                // conversion.  So we need to make one last check before
                // exiting.
                if (Character.toLowerCase(u1) == Character.toLowerCase(u2)) {
                    continue;
                }
            }
            return false;
        }
        return true;
    }

    String(char[] value, boolean share) {
        // assert share : "unshared not supported";
        this.value = value;
    }

    char[] val = value;   /* avoid getfield opcode */

    public boolean contentEquals(CharSequence cs) {
        if (value.length != cs.length())
            return false;
        // Argument is a StringBuffer, StringBuilder
        if (cs instanceof AbstractStringBuilder) {
            char v1[] = value;
            char v2[] = ((AbstractStringBuilder) cs).getValue();
            int i = 0;
            int n = value.length;
            while (n-- != 0) {
                if (v1[i] != v2[i])
                    return false;
                i++;
            }
            return true;
        }
        // Argument is a String
        if (cs.equals(this))
            return true;
        // Argument is a generic CharSequence
        char v1[] = value;
        int i = 0;
        int n = value.length;
        while (n-- != 0) {
            if (v1[i] != cs.charAt(i))
                return false;
            i++;
        }
        return true;
    }

附: 开发者工具

• IDEA: 比较给力的Java IDE, 用过都说好(“自从用了IDEA, 写代码越来越有劲儿了”). 非常多很赞的功能, 如对Git、Maven的原生支持, 自动代码提示, 自带命令行, 黑色主题, UML类图生成… 而且现在IDEA家族也越来越强, Android开发的Android Studio、IOS的AppCode、C/C++的CLion、Python的PyCharm、PHP的PhpStorm、前端的WebStorm等等, 详细可查看Jet Brains官网.
• Git&GitHub: Git就不用多做介绍了, 算是开发者居家旅行之必备吧. 这方面的书/视频很多, 但在此我只推荐一部文档: 廖雪峰的Git教程. 虽然Git内容繁多, 但这篇文档却直取要害, 非常实用, 读了很多遍.
• Maven: Maven方面我也是新手, 在此我只推荐一部还不错的Maven方面的书, Maven实战, 一部国人写的实战类书籍.
• SQLPro for MySQL: 一款MySQL-GUI客户端, 用过MySQL-WorkBench、Navicat、Sequel Pro, 但最后还是选择的SQLPro for MySQL.
• ProcessOn: 免费绘图网站, UML、流程图、网络拓扑… 上手容易.
• Markdown: 这方面我也是初学者, 推荐两个客户端Cmd Markdown、MWeb.
• JSON查看&编辑
  这方面除了TextLab没有发现其他好用的客户端, 只能推荐几个网站:
  
  • qqe2.com: 对JSON数据排错提示功能很强大;
  • json.cn, 查看JSON数据非常美观, 支持代码折叠.
• RegExRx
  Mac上非常好用的正则表达式匹配引擎, 用于测试正则表达式书写的正确与否.
• iTerm2
  忘掉Mac自带的终端吧, iTerm你值得拥有.
• Alfred
  最后, 推荐Mac效率神器Alfred, 推荐博客: 从零开始学习 Alfred（上）：基础功能及设置, 其他功能还在探索.

在此只推荐了我所知道和常用一些小工具, 欢迎同学补充.