Java Tester. Home Page. Java security news. October 17, 2017 Java 8 Update 151 has been released. It is the new security baseline and is due to expire January 16. These options control how garbage collection GC is performed by the Java Hot. Spot VM. XX Aggressive. Heap. Enables Java heap optimization. This sets various parameters to be optimal for long running jobs with intensive memory allocation, based on the configuration of the computer RAM and CPU. By default, the option is disabled and the heap is not optimized. XX Always. Pre. Touch. Enables touching of every page on the Java heap during JVM initialization. This gets all pages into the memory before entering the main method. The option can be used in testing to simulate a long running system with all virtual memory mapped to physical memory. By default, this option is disabled and all pages are committed as JVM heap space fills. XX CMSClass. Unloading. Enabled. Enables class unloading when using the concurrent mark sweep CMS garbage collector. This option is enabled by default. To disable class unloading for the CMS garbage collector, specify XX CMSClass. Unloading. Enabled. XX CMSExp. Avg. Factorpercent. ECDevGuide/latest/5.01-Eclipse-Java_files/image014.png' alt='Java Installation Tool' title='Java Installation Tool' />An integrated, interactive Java development environment, featuring class structure diagrams, interactive invocation and an easytouse interface. BlueJ was developed. Sets the percentage of time 0 to 1. By default, the exponential averages factor is set to 2. The following example shows how to set the factor to 1. XX CMSExp. Avg. Factor1. XX CMSInitiating. Occupancy. Fractionpercent. Java Installation Tool' title='Java Installation Tool' />Sets the percentage of the old generation occupancy 0 to 1. CMS collection cycle. The default value is set to 1. Any negative value including the default implies that XX CMSTrigger. Ratio is used to define the value of the initiating occupancy fraction. The following example shows how to set the occupancy fraction to 2. XX CMSInitiating. Occupancy. Fraction2. XX CMSScavenge. Before. Remark. Enables scavenging attempts before the CMS remark step. By default, this option is disabled. XX CMSTrigger. Ratiopercent. Sets the percentage 0 to 1. XX Min. Heap. Free. Ratio that is allocated before a CMS collection cycle commences. The default value is set to 8. The following example shows how to set the occupancy fraction to 7. XX CMSTrigger. Ratio7. XX Conc. GCThreadsthreads. Sets the number of threads used for concurrent GC. The default value depends on the number of CPUs available to the JVM. For example, to set the number of threads for concurrent GC to 2, specify the following option. XX Conc. GCThreads2. XX Disable. Explicit. GCEnables the option that disables processing of calls to System. This option is disabled by default, meaning that calls to System. If processing of calls to System. JVM still performs GC when necessary. XX Explicit. GCInvokes. Concurrent. Enables invoking of concurrent GC by using the System. This option is disabled by default and can be enabled only together with the XX Use. Conc. Mark. Sweep. GC option. XX Explicit. GCInvokes. Concurrent. And. Unloads. Classes. Enables invoking of concurrent GC by using the System. GC cycle. This option is disabled by default and can be enabled only together with the XX Use. Conc. Mark. Sweep. GC option. XX G1. Heap. Region. Sizesize. Sets the size of the regions into which the Java heap is subdivided when using the garbage first G1 collector. The value can be between 1 MB and 3. MB. The default region size is determined ergonomically based on the heap size. The following example shows how to set the size of the subdivisions to 1. MB. XX G1. Heap. Region. Size1. 6m. XX G1. Print. Heap. Regions. Enables the printing of information about which regions are allocated and which are reclaimed by the G1 collector. By default, this option is disabled. XX G1. Reserve. Percentpercent. Sets the percentage of the heap 0 to 5. G1 collector. By default, this option is set to 1. The following example shows how to set the reserved heap to 2. XX G1. Reserve. Percent2. XX Initial. Heap. Sizesize. Sets the initial size in bytes of the memory allocation pool. This value must be either 0, or a multiple of 1. MB. Append the letter k or K to indicate kilobytes, m or M to indicate megabytes, g or G to indicate gigabytes. The default value is chosen at runtime based on system configuration. See the section Ergonomics in Java SE Hot. Spot Virtual Machine Garbage Collection Tuning Guide at http docs. The following examples show how to set the size of allocated memory to 6 MB using various units. XX Initial. Heap. Size6. 29. 14. 56. XX Initial. Heap. Size6. 14. 4k. XX Initial. Heap. Size6m. If you set this option to 0, then the initial size will be set as the sum of the sizes allocated for the old generation and the young generation. The size of the heap for the young generation can be set using the XX New. Size option. XX Initial. Survivor. Ratioratio. Sets the initial survivor space ratio used by the throughput garbage collector which is enabled by the XX Use. Parallel. GC andor XX Use. Parallel. Old. GC options. Adaptive sizing is enabled by default with the throughput garbage collector by using the XX Use. Parallel. GC and XX Use. Parallel. Old. GC options, and survivor space is resized according to the application behavior, starting with the initial value. If adaptive sizing is disabled using the XX Use. Adaptive. Size. Policy option, then the XX Survivor. Ratio option should be used to set the size of the survivor space for the entire execution of the application. The following formula can be used to calculate the initial size of survivor space S based on the size of the young generation Y, and the initial survivor space ratio R. The 2 in the equation denotes two survivor spaces. The larger the value specified as the initial survivor space ratio, the smaller the initial survivor space size. By default, the initial survivor space ratio is set to 8. If the default value for the young generation space size is used 2 MB, the initial size of the survivor space will be 0. MB. The following example shows how to set the initial survivor space ratio to 4. XX Initial. Survivor. Ratio4. XX Initiating. Heap. Occupancy. Percentpercent. Sets the percentage of the heap occupancy 0 to 1. GC cycle. It is used by garbage collectors that trigger a concurrent GC cycle based on the occupancy of the entire heap, not just one of the generations for example, the G1 garbage collector. By default, the initiating value is set to 4. A value of 0 implies nonstop GC cycles. The following example shows how to set the initiating heap occupancy to 7. XX Initiating. Heap. Occupancy. Percent7. XX Max. GCPause. Millistime. Sets a target for the maximum GC pause time in milliseconds. This is a soft goal, and the JVM will make its best effort to achieve it. By default, there is no maximum pause time value. The following example shows how to set the maximum target pause time to 5. XX Max. GCPause. Millis5. XX Max. Heap. Sizesize. Sets the maximum size in byes of the memory allocation pool. This value must be a multiple of 1. MB. Append the letter k or K to indicate kilobytes, m or M to indicate megabytes, g or G to indicate gigabytes. The default value is chosen at runtime based on system configuration. For server deployments, XX Initial. Heap. Size and XX Max. Heap. Size are often set to the same value. See the section Ergonomics in Java SE Hot. Spot Virtual Machine Garbage Collection Tuning Guide at http docs. The following examples show how to set the maximum allowed size of allocated memory to 8. MB using various units. XX Max. Heap. Size8. XX Max. Heap. Size8. XX Max. Heap. Size8. The XX Max. Heap. Size option is equivalent to Xmx. XX Max. Heap. Free. Ratiopercent. Java Application Installer. Advanced Installer is the only Windows. Installer authoring tool with built in support for Java. Windows OS and making them. Using Advanced Installer you can create MSI packages for your. Java applications, and allow your application to use the. Windows Installer features. Why Windows Installer Best Windows integration. Zero overhead installation packages. Using Windows Installer gives you the best possible. Windows Platform. Windows. Installer is the standard Windows install technology and it is. Microsoft for any application intending to meet the. Windows logo certification. Because the Windows Installer engine is included in the. Microsoft operating systems, distributed with the latest. Office and also freely downloadable on the Internet. Advanced Installer and the packages it creates contain 1. Windows native code and technologies. This ensures the smallest. What can Windows Installer do for your Java programs. Installuninstall files, registry keys, environment. Create shortcuts in the Start menu or on the desktop. File associations. Bundle, or download and install a. JREUnattended installs. Operating System version check. Digitally signing your install packages. Read more Advanced Installer. Features. Native Java launcher. Your own process name, file icon and version. Instant on splash screen. JRE auto detection and version check. Runs as a GUIconsole application or a Win. Advanced Installer provides a native launcher for. Java applications. Using this launcher your users will. Java programs just like regular Windows native. The native launcher provides a fast and friendly start up. Java applications. It will start. by instantly displaying a splash screen, after which it will look. JRE. Finally, it will load the JRE and. Any unexpected error will be presented to. Mac OS X package. Build standard, native bundles to install your Java programs. Mac OS XAdvanced Installer has the ability to create. Java applications for installing on Mac OS. X. They respect the industry guidelines, supporting all the. The packages are strictly native. Java installers. The cross platform installation elements are included. Windows specific ones are ignored. The Mac OS X. build is fully customizable with its own file layout. Includes Java 7 applications support for deployment on Mac. OS X. Windows Installer vs. Cross Platform installers. Disney Mix It Plug In more. The main advantage of a cross platform installer is its. However this ability comes often at the expense of the. Operating System integration that a. Cross platform installers come with their own proprietary. This engine must be included in. Megabyte. Windows Installer is a standard, well. Windows and most popular applications. Most cross platform installers are themselves written in. Java. Because of that, they require that a JRE be installed before. Otherwise, incomprehensible error messages are. Furthermore, they sport a non standard look and feel.