Note – In static mode you can test specified classes in another runtime environment. For example, this can be useful to analyze APIs that are part of a Java SE platform

1.4.2environment when the SignatureTest command is run on a Java SE platform version 5.0.

Constant Checking in Differing Run Modes

The requirements related to constant checking differ in binary and source compatibility testing. Although constant checking can be applied to binary compatibility, it is a necessary prerequisite for source code compatibility. Use the -staticmode to enforce strict constant checking in source code compatibility testing.

When running a signature test in source compatibility mode and using the static mode, constant checking is strict and two way. This means that all the constant fields and their related values specified in the reference API must have the same values in the API under test. Likewise, all the constant fields and their related values specified in the API under test must have the same values in the reference API.

In binary compatibility mode, the requirements related to constant checking are less strict. The signature test verifies that all the constant fields and associated values contained in the reference API are also available in the API under test. If any field values are missing or different, it reports an error. However, the signature test does not report an error if constant values are found in the API under test that are not available in the reference API.

Generics Checking in Binary Mode

The information related to generics is not used by the Java Virtual Machine1 at runtime. This information is used only by the compiler at compile time.

In binary mode the SignatureTest command compares the signatures of parameterized types after omitting the type parameters and arguments from both the signature file and the analyzed API (termed type erasure). This is to ensure that they are compatible at runtime. See The Java Language Specification, Third Edition, for a detailed description of type erasure.

The bridge methods that are generated by the compiler during type erasure are not a part of the API and so they are ignored by the SigTest tool.

1. The terms "Java Virtual Machine" and "JVM" mean a Virtual Machine for the Java™ platform

Chapter 2 Using the Signature Test Tool

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Sun Microsystems 2 manual Constant Checking in Differing Run Modes, Generics Checking in Binary Mode
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2 specifications

Sun Microsystems, founded in 1982, was a significant player in the computing industry, best known for its innovative technology solutions and workstations, particularly the Sun-4, which represented a key milestone in the company's history. The Sun-4 architecture, launched in 1987, utilized the SPARC (Scalable Processor Architecture) RISC processor, notable for its high performance and scalability.

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In summary, the Sun Microsystems 2 and its successive innovations in workstation technology highlighted the company's forward-thinking approach. By integrating powerful performance with open systems, robust operating systems, and advanced networking capabilities, Sun laid the groundwork for modern computing, influencing various sectors from academia to enterprise solutions. Even after its acquisition by Oracle in 2010, the legacy of Sun Microsystems continues to be felt across the computing industry.
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