Java: Difference between revisions
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| Line 38: | Line 38: | ||
Error output in logfile. | Error output in logfile. | ||
=multicast test= | =multicast test= | ||
host1: java MulticastReceiver | |||
Starting multicast receiver in group 224.1.0.1 on port 14454 | Starting multicast receiver in group 224.1.0.1 on port 14454 | ||
hello | hello | ||
| Line 45: | Line 45: | ||
On host2: | On host2: | ||
host2: java MulticastSender | |||
hello | hello | ||
how are you | how are you | ||
Revision as of 18:47, 10 February 2017
Java information
To list keys in java keystore.
/usr/java/jre1.6.0_03/bin/keytool --list --keystore /usr/java/jre1.6.0_03/lib/security/cacerts
Import key in java keystore.
openssl x509 -outform der -in certificate.pem -out certificate.der keytool -import -alias your-alias -keystore cacerts -file certificate.der
List content of der.
openssl x509 -in BPClass3RootCA.cer -inform der -noout -text
show jar file signing
jarsigner -verify -verbose -certs file.jar
modify settiings
jcontrol
connect via jmx
jcontrol
connect to jvm
jvisualvm
java options
Sets the initial memory size
-Xms256m / -ms256m
Specifies the maximum memory size
-Xmx2048m / -mx20148m
install java
#!/bin/bash JDK_VERSION=8u71 JDK_BUILD_VERSION=b15 cd /tmp curl -LO "http://download.oracle.com/otn-pub/java/jdk/$JDK_VERSION-$JDK_BUILD_VERSION/jdk-$JDK_VERSION-linux-x64.rpm" -H 'Cookie: oraclelicense=accept-securebackup-cookie' rpm -i jdk-$JDK_VERSION-linux-x64.rpm rm -f jdk-$JDK_VERSION-linux-x64.rpm
heap utilization
jstat -gc ${PID}
stack trace
Error output in logfile.
multicast test
host1: java MulticastReceiver Starting multicast receiver in group 224.1.0.1 on port 14454 hello how are you On host2: host2: java MulticastSender hello how are you