Issue

• サーバーのログに、例外 'Too many open files' が記録されます。

        Socket accept failed java.net.SocketException:Too many open files
                at java.net.PlainSocketImpl.socketAccept(Native Method)
                at java.net.PlainSocketImpl.accept(Unknown Source)
                at java.net.ServerSocket.implAccept(Unknown Source)
                ...
                ...
        java.io.FileNotFoundException: filename (Too many open files)
                at java.io.FileInputStream.open(Native Method)
                at java.io.FileInputStream.<init>(FileInputStream.java:106)
                at java.io.FileInputStream.<init>(FileInputStream.java:66)
                at java.io.FileReader.<init>(FileReader.java:41)