Jannovar is a Java program that runs using the Java Virtual Machine (JVM). The program does not allocate memory directly but through the JVM which uses a fixed maximal memory limit. If Jannovar terminates by throwing an exception java.lang.OutOfMemoryError then you have to increase the memory limit of the JVM.
One way of doing this by setting the environment variable JAVA_TOOL_OPTIONS. For example, the following line increases the available memory to 2 GB of RAM.
export JAVA_TOOL_OPTIONS="-Xms2G -Xmx2G"If you prefer, then you can also pass these options to the invokation of JVM. The following Jannovar invocation allows to use up to 2 GB of RAM:
java -Xms2G -Xmx2G -jar jannovar-cli-.jar [...]