The initial part of [[Java]] application is [[AOT]] compiled and as such it ''starts blazingly'' fast. At any time it can launch [[HotSpot]] [[JVM]] in the same process and run the remaining parts of the [[Java]] application ''more dynamically'' and [[JIT]] compile them.

The initial part of [[Java]] application is [[AOT]] compiled and as such it ''starts blazingly'' fast. At any time it can launch [[HotSpot]] [[JVM]] in the same process and run the remaining parts of the [[Java]] application ''more dynamically'' and [[JIT]] compile them.

See [https://github.com/jtulach/graalvm-native-libs github project] with the essential libraries.

See my new [https://github.com/jtulach/graalvm-native-libs github project] with the essential libraries.

The essential part of the [[Dual JVM]] system design includes an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of data allocated as direct NIO {{JDK|java/nio|Buffer}}''s between those two [[JVM]]s.

The essential part of the [[Dual JVM]] system design includes an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of data allocated as direct NIO {{JDK|java/nio|Buffer}}''s between those two [[JVM]]s.

The initial part of [[Java]] application is [[AOT]] compiled and as such it ''starts blazingly'' fast. At any time it can launch [[HotSpot]] [[JVM]] in the same process and run the remaining parts of the [[Java]] application ''more dynamically'' and [[JIT]] compile them.

The initial part of [[Java]] application is [[AOT]] compiled and as such it ''starts blazingly'' fast. At any time it can launch [[HotSpot]] [[JVM]] in the same process and run the remaining parts of the [[Java]] application ''more dynamically'' and [[JIT]] compile them.

The essential part of the [[Dual JVM]] system design includes an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of data allocated as direct NIO {{JDK|java/nio|Buffer}}''s between those two [[JVM]]s.

The essential part of the [[Dual JVM]] system design includes an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of data allocated as direct NIO {{JDK|java/nio|Buffer}}''s between those two [[JVM]]s.

The initial part of [[Java]] application is [[AOT]] compiled and as such it ''starts blazingly'' fast. At any time it can launch [[HotSpot]] [[JVM]] in the same process and run the remaining parts of the [[Java]] application ''more dynamically'' and [[JIT]] compile them.

The initial part of [[Java]] application is [[AOT]] compiled and as such it ''starts blazingly'' fast. At any time it can launch [[HotSpot]] [[JVM]] in the same process and run the remaining parts of the [[Java]] application ''more dynamically'' and [[JIT]] compile them.

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of data allocated as direct NIO {{JDK|java/nio|Buffer}}''s between those two [[JVM]]s.

The essential part of the [[Dual JVM]] system design includes an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of data allocated as direct NIO {{JDK|java/nio|Buffer}}''s between those two [[JVM]]s.

The initial part of [[Java]] application is [[AOT]] compiled and as such it ''starts blazingly'' fast. At any time it can launch [[HotSpot]] [[JVM]] in the same process and run the remaining parts of the [[Java]] application ''more dynamically'' and [[JIT]] compile them.

The initial part of [[Java]] application is [[AOT]] compiled and as such it ''starts blazingly'' fast. At any time it can launch [[HotSpot]] [[JVM]] in the same process and run the remaining parts of the [[Java]] application ''more dynamically'' and [[JIT]] compile them.

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of data allocated as direct NIO {{JDK|java/nio|Buffer}}''s between those two [[JVM]]s.

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of data allocated as direct NIO {{JDK|java/nio|Buffer}}''s between those two [[JVM]]s.

A heroic effort was needed to marry the fast start of the [[Enso]] engine (to be attributed to AOT compilation) with the need to dynamically load JVM classes. The effort is being called a ''"dual JVM"'' (see [https://docs.google.com/presentation/d/1f0ygesiiUbMe3rEXVonDPzLI0TyKIWkMeLyhh4okkKE slides]) because there are two [[Java]] virtual machines running in the single [[Enso]] process communicating effectively with each other.

A heroic effort was needed to marry the fast start of the [[Enso]] engine (to be attributed to [[AOT]] compilation) with the need to dynamically load [[JVM]] classes. The effort is being called a ''"dual JVM"'' (see [https://docs.google.com/presentation/d/1f0ygesiiUbMe3rEXVonDPzLI0TyKIWkMeLyhh4okkKE slides]) because there are two [[Java]] virtual machines running in the single [[Enso]] process communicating effectively with each other.

The initial part of [[Java]] application is [[AOT]] compiled and as such it ''starts blazingly'' fast. At any time it can launch [[HotSpot]] [[JVM]] in the same process and run the remaining parts of the [[Java]] application ''more dynamically'' and [[JIT]] compile them.

The initial part of [[Java]] application is [[AOT]] compiled and as such it ''starts blazingly'' fast. At any time it can launch [[HotSpot]] [[JVM]] in the same process and run the remaining parts of the [[Java]] application ''more dynamically'' and [[JIT]] compile them.

=== Zero Copy Data Exchange ===

=== Zero Copy Data Exchange ===

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of {{JDK|java/nio|Buffer}}'' data (typically) in the Apache Arrow format between those two [[JVM]]s.

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of data allocated as direct NIO {{JDK|java/nio|Buffer}}''s between those two [[JVM]]s.

=== Zero Copy Data Exchange ===

=== Zero Copy Data Exchange ===

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of {{JDK|java/nio/|Buffer}}'' data (typically) in the Apache Arrow format between those two [[JVM]]s.

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of {{JDK|java/nio|Buffer}}'' data (typically) in the Apache Arrow format between those two [[JVM]]s.

=== Zero Copy Data Exchange ===

=== Zero Copy Data Exchange ===

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of {{JDK|java/nio/buffer|Buffer}}'' data (typically) in the Apache Arrow format between those two [[JVM]]s.

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of {{JDK|java/nio/|Buffer}}'' data (typically) in the Apache Arrow format between those two [[JVM]]s.

=== Zero Copy Data Exchange ===

=== Zero Copy Data Exchange ===

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of {{JDK|java.nio.buffer|Buffer}}'' data (typically) in the Apache Arrow format between those two [[JVM]]s.

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of {{JDK|java/nio/buffer|Buffer}}'' data (typically) in the Apache Arrow format between those two [[JVM]]s.

=== [[Apache]] Arrow ===

=== Zero Copy Data Exchange ===

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of {{JDK|java.nio.buffer|Buffer}}'' data (typically) in the Apache Arrow format between those two [[JVM]]s.

The essential part of the [[Dual JVM]] system is an ''effective exchange'' of data between those two [[JVM]]s. The system allows '''zero copy''' exchange of {{JDK|java.nio.buffer|Buffer}}'' data (typically) in the Apache Arrow format between those two [[JVM]]s.