IBM SDK, Java Technology Edition Version 7 Release 1 AIX User Guide IBM IBM SDK, Java Technology Edition Version 7 Release 1 AIX User Guide IBM Note Before you use this information and the product it supports, read the information in “Notices” on page 623. Copyright information This edition of the user guide applies to the IBM SDK, Java Technology Edition, Version 7 Release 1, for all supported AIX architectures, and to all subsequent releases, modifications, and fix packs, until otherwise indicated in new editions. This guide applies to the following programs: v IBM 32-bit SDK for AIX, Java Technology Edition, Version 7 Release 1 v IBM 64-bit SDK for AIX, Java Technology Edition, Version 7 Release 1 Portions © Copyright 1997, 2018, Oracle and/or its affiliates. © Copyright IBM Corporation 2011, 2018. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Preface .............. vii CORBA .............. 113 RMI and RMI-IIOP .......... 114 Chapter 1. Product overview ...... 1 Java IDL or RMI-IIOP? ......... 114 RMI-IIOP limitations .......... 114 Introduction .............. 1 Examples of client–server applications .... 115 IBM Software Developers Kit (SDK) ..... 2 Using the ORB ............ 119 Runtime Environment .......... 4 How the ORB works .......... 121 J9 Virtual Machine (JVM) ......... 6 Additional features of the ORB ...... 129 What's new ............... 6 The Java Native Interface (JNI) ....... 132 First release.............. 7 Overview of JNI ........... 132 Service refresh 1 ............ 9 The JNI and the Garbage Collector ..... 133 Service refresh 2 ............ 10 Copying and pinning.......... 138 Service refresh 3 ............ 13 Handling exceptions .......... 139 Service refresh 4 ............ 15 Synchronization ........... 140 Packed object evaluation technology ...... 16 Debugging the JNI .......... 140 Packed objects ............ 16 JNI checklist............. 142 Conventions and terminology ........ 62 Other sources of information ........ 64 Accessibility .............. 64 Chapter 3. Planning......... 143 Migrating from earlier releases of the IBM SDK, Chapter 2. Understanding the Java Technology Edition .......... 143 components ............ 65 Version compatibility ........... 145 Supported environments ......... 146 The building blocks of the IBM Virtual Machine for Additional information for AIX ....... 146 Java ................. 65 Java application stack .......... 66 Chapter 4. Installing and configuring Components of the IBM Virtual Machine for Java 67 Memory management ........... 69 the SDK and Runtime Environment .. 149 Overview of memory management ..... 69 Installing from an InstallAnywhere package ... 150 Allocation .............. 71 Completing an attended installation ..... 150 Detailed description of global garbage collection 74 Completing an unattended installation .... 151 Generational Concurrent Garbage Collector... 83 Interrupted installation ......... 152 Balanced Garbage Collection policy ..... 84 Known issues and limitations ....... 153 Metronome Garbage Collection policy .... 91 Relocating an installp package........ 153 How to do heap sizing ......... 92 Upgrading the SDK ........... 153 Interaction of the Garbage Collector with Verification .............. 154 applications ............. 94 Setting the path ............ 155 How to coexist with the Garbage Collector ... 95 Setting the class path ........... 155 Frequently asked questions about the Garbage Updating your SDK or runtime environment for Collector .............. 98 Daylight Saving Time changes........ 156 Class loading ............. 101 The parent-delegation model ....... 102 Chapter 5. Developing Java Namespaces and the runtime package .... 103 applications ............ 157 Custom class loaders .......... 103 Using XML .............. 157 Class data sharing ............ 104 Migrating to the XL-TXE-J ........ 159 The JIT compiler ............ 105 Securing Java API for XML processing (JAXP) JIT compiler overview ......... 105 against malformed input ........ 161 How the JIT compiler optimizes code .... 106 XML reference information ........ 162 Frequently asked questions about the JIT Debugging Java applications ........ 166 compiler .............. 108 Java Debugger (JDB) .......... 167 The AOT compiler............ 109 Determining whether your application is running Java Remote Method Invocation ....... 110 on a 32-bit or 64-bit JVM ......... 168 The RMI implementation ........ 110 Porting Java applications to 64-bit systems ... 168 Thread pooling for RMI connection handlers .. 111 General porting considerations ...... 168 Understanding distributed garbage collection 111 Porting native code from 32-bit to 64-bit systems 171 Debugging applications involving RMI .... 112 JNI considerations ........... 172 The ORB ............... 112 Usage of the JNI interface ........ 174 © Copyright IBM Corp. 2011, 2018 iii JVMPI and JVMDI interfaces ....... 174 More effective heap usage using compressed How the JVM processes signals ....... 175 references ............. 216 Signals used by the JVM ........ 175 Pause time ............. 216 Linking a native code driver to the Pause time reduction .......... 217 signal-chaining library ......... 177 Environments with very full heaps ..... 218 Writing JNI applications .......... 178 Using the Metronome Garbage Collector ... 218 Supported compilers .......... 178 Dynamic Logical Partitioning (DLPAR) support 225 JNI compatibility ........... 178 Live application mobility on AIX WPAR .... 226 JNI runtime linking .......... 179 Using the IPv6 extensions ......... 227 Example of using AIX shared libraries .... 182 Support for bidirectional data ........ 227 Support for thread-level recovery of blocked Special Arabic characters ........ 228 connectors .............. 183 Known limitations........... 230 CORBA support ............ 184 Euro symbol support ........... 230 System properties for tracing the ORB .... 185 Scaling support............. 230 System properties for tuning the ORB .... 185 Configuring large page memory allocation ... 231 Java security permissions for the ORB .... 186 SDK use of AIX large program support..... 232 ORB implementation classes ....... 186 Automatic LDR_CNTRL=MAXDATA values .. 232 RMI over IIOP ............. 187 Manual LDR_CNTRL=MAXDATA values ... 234 RMI-IIOP Programmer's Guide ...... 187 System resource limits and the ulimit command 235 Implementing the Connection Handler Pool for AIX Stack Execution Disable ........ 236 RMI ................ 194 AIX native threads ........... 194 Chapter 8. Performance ....... 239 Developing Java applications ........ 194 Class data sharing between JVMs ...... 239 Support for XToolkit ........... 194 Overview of class data sharing ...... 239 Support for the Java Attach API ....... 195 Class data sharing command-line options ... 241 The Data Access Accelerator Library...... 197 Creating, populating, monitoring, and deleting a cache ............... 242 Chapter 6. Plug-in, Applet Viewer and Performance and memory consumption ... 243 Web Start ............. 201 Considerations and limitations of using class Using the Java plug-in .......... 201 data sharing ............. 243 Supported browsers .......... 201 Adapting custom class loaders to share classes 246 Installing the Java plug-in ........ 202 | Enabling hardware compression acceleration on Changing the properties of the Java Plug-in .. 202 | Power Systems ............. 246 Common Document Object Model (DOM) Performance problems .......... 247 support .............. 202 Using DBCS parameters ......... 203 Chapter 9. Security ......... 249 Working with applets .......... 203 Security considerations .......... 249 Running and debugging applets with the Security components and tools ....... 251 Applet Viewer ............ 203 Java Applet Viewer and the classpath .... 204 Chapter 10. Troubleshooting and Using Web Start ............ 204 support .............. 253 Running Web Start .......... 205 Submitting problem reports ........ 253 WebStart Secure Static Versioning...... 206 Problem determination .......... 253 Distributing Java applications ........ 206 First steps in problem determination .... 253 AIX problem determination ....... 255 Chapter 7. Running Java applications 207 NLS problem determination ....... 291 The java and javaw commands ....... 207 ORB problem determination ....... 293 Obtaining version information....... 207 | Hardware compression acceleration issues on Specifying Java options and system properties 209 | Power Systems ............ 307 Standard options ........... 209 Attach API problem determination ..... 308 Globalization of the java command ..... 210 Using diagnostic tools .......... 312 Working with the LIBPATH environment variable 211 Overview of the available diagnostic tools... 312 Working with the LDR_CNTRL environment variable 212 Using the IBM Monitoring and Diagnostic Tools 319 The Just-In-Time (JIT) compiler ....... 213 Using dump agents .......... 321 Disabling the JIT ........... 213 Using Javadump ........... 340 Enabling the JIT ........... 214 Using Heapdump ........... 363 Determining whether the JIT is enabled ... 214 Using system dumps and the dump viewer .. 373 Specifying a garbage collection policy ..... 214 Tracing Java applications and the JVM .... 393 Garbage collection options ........ 215 JIT and AOT problem determination .... 430 IBM Support Assistant Data Collector .... 436 iv IBM SDK, Java Technology Edition, Version 7 Release 1: AIX User Guide Garbage Collector