cat >>/etc/profile <<EOF
export JAVA_HOME=/opt/jdk1.8.0_221
export JRE_HOME=/opt/jdk1.8.0_221/jre
export PATH=\$PATH:/opt/jdk1.8.0_221/bin
export CLASSPATH=./:/opt/jdk1.8.0_221/lib:/opt/jdk1.8.0_221/jre/lib
EOF
cat >>/etc/security/limits.conf <<EOF
* soft nofile 65535
* hard nofile 65535
EOF
ulimit -SHn 51200