| # APT | |
| ## Package version before installing it | |
| ``` | |
| apt list azure-cli | |
| Listing... Done | |
| azure-cli/bullseye 2.33.1-1~bullseye all | |
| N: There are 9 additional versions. Please use the '-a' switch to see them. | |
| apt list -a azure-cli | |
| Listing... Done |
| ///usr/bin/env jbang "$0" "$@" ; exit $? | |
| import java.util.List; | |
| import java.util.LinkedList; | |
| public class InternStringsExample { | |
| public static void main(String... args) throws Exception { | |
| List<String> strings = new LinkedList<String>(); |
| ///usr/bin/env jbang "$0" "$@" ; exit $? | |
| //DEPS org.apache.commons:commons-lang3:3.12.0 | |
| //JAVA_OPTIONS -XX:-UseAdaptiveSizePolicy | |
| //JAVA_OPTIONS -Xms16m -Xmx16m | |
| //JAVA_OPTIONS -XX:NewSize=3m -XX:MaxNewSize=3m -XX:SurvivorRatio=1 | |
| //JAVA_OPTIONS -XX:MaxTenuringThreshold=5 | |
| //JAVA_OPTIONS -Xlog:gc* | |
| //JAVA_OPTIONS -XX:+UseSerialGC |
| //JAVA_OPTIONS -Xms8m -Xmx8m -XX:+UseSerialGC | |
| //JAVA_OPTIONS -XX:-DisableExplicitGC | |
| /// https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/ref/Cleaner.html | |
| import java.lang.AutoCloseable; | |
| import java.lang.ref.Cleaner; | |
| public class CleanerAPIAutoCloseableExample{ |
| ///usr/bin/env jbang "$0" "$@" ; exit $? | |
| //DEPS org.apache.commons:commons-lang3:3.12.0 | |
| //JAVA_OPTIONS -Xms128m -Xmx128m | |
| //JAVA_OPTIONS -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC | |
| //JAVA_OPTIONS -XX:+HeapDumpOnOutOfMemoryError | |
| import org.apache.commons.lang3.RandomStringUtils; |
jbang run --java-options="-XX:-UseStringDeduplication" https://gist.github.com/misTrasteos/225ca2f29996a20f88c8ddf0be3cd3b2#file-stringdeduplicationexample-javaSame number of String and char[] objects
jbang run --java-options="-XX:+UseStringDeduplication" https://gist.github.com/misTrasteos/225ca2f29996a20f88c8ddf0be3cd3b2#file-stringdeduplicationexample-java
| ///usr/bin/env jbang "$0" "$@" ; exit $? | |
| //DEPS org.openjdk.jol:jol-core:0.16 | |
| import org.openjdk.jol.info.ClassLayout; | |
| import org.openjdk.jol.info.GraphLayout; | |
| public class JolTest { | |
| static class Patient1{ |
jbang run https://gist.github.com/misTrasteos/e616b87452b215db116448216da59636\#file-stackorheapallocation-java
You will get a java.lang.OutOfMemoryError: Java heap space. As we are using no-op Epsilon GC and we are allocation plenty of Integer objects in the heap.
jbang run -D=PRIMITIVE https://gist.github.com/misTrasteos/e616b87452b215db116448216da59636\#file-stackorheapallocation-java
| //usr/bin/env jbang "$0" "$@" ; exit $? | |
| //DEPS io.quarkus:quarkus-resteasy:2.5.1.Final | |
| //DEPS io.quarkus:quarkus-resteasy-jackson:2.5.1.Final | |
| //JAVAC_OPTIONS -parameters | |
| //JAVA_OPTIONS -Djava.util.logging.manager=org.jboss.logmanager.LogManager | |
| import io.quarkus.runtime.Quarkus; | |
| import javax.enterprise.context.ApplicationScoped; |
| ///usr/bin/env jbang "$0" "$@" ; exit $? | |
| //JAVA_OPTIONS -Xms32m -Xmx32m -Xlog:gc* -XX:+UseSerialGC | |
| /// -XX:+HeapDumpBeforeFullGC | |
| /// jbang run -D=WEAK WeakHashMapPoc.java for infinite execution as weak references are collected before an OOO | |
| /// jbang run -D=STRONG -D=WEAK WeakHashMapPoc.java OOO even using a WeakHashMap, as keys are strongly referenced | |
| /// jbang run WeakHashMapPoc.java for an OOO as simple Map keys are strongly referenced |