Java Debugger Break on Next Called Function Command
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Solution Overview
Problem
Debugging Java applications that branch into multiple possible method or function calls requires cumbersome and undesirable multiple breakpoint settings, making it inefficient to stop the debugger at the desired location.
Innovation Solution
A 'break on next called function' (BNCF) command is introduced in the Java debugger agent, allowing a flag to be set in the Java virtual machine to stop execution at the beginning of the next called method or function, detected by predefined opcodes such as 'invokevirtual', 'invokespecial', and 'invokeinterface', simplifying breakpoint management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple breakpoints are set at each possible branch of the application to debug all method calls, then debugging coverage is improved, but device complexity and ease of operation deteriorate due to the cumbersome nature of setting multiple breakpoints
Solution Approach 1:
The breakpoint command is enhanced to serve multiple functions: it can set breakpoints at specific locations as before, and additionally set a flag that automatically breaks at the next method invocation regardless of which method is called. This universal approach handles both specific and general debugging needs with a single command mechanism.
Solution Approach 2:
The debugging system automatically monitors method invocations and detects when to break based on the set flag, eliminating the need for manual intervention to set multiple breakpoints. The system serves itself by automatically identifying method call boundaries and triggering breakpoints without user assistance.
2Reliability
If multiple breakpoints are set at each possible branch of the application to debug all method calls, then debugging coverage is improved, but device complexity worsens due to the increased number of breakpoint management operations
Solution Approach 1:
A single breakpoint command with an added flag parameter provides universal functionality that replaces the need for multiple separate breakpoint settings. The command structure remains familiar but gains the capability to handle dynamic method invocation breakpoints, reducing the number of management operations required.
Solution Approach 2:
The functionality of setting specific breakpoints and detecting method invocations is merged into a single breakpoint command. The command combines the traditional breakpoint setting mechanism with automatic method invocation detection, consolidating what would otherwise require multiple separate operations into one unified action.
3Ease of operation
If traditional breakpoint settings are used at specific locations, then ease of operation is maintained, but productivity deteriorates due to the time required to manually set and manage multiple breakpoints
Solution Approach 1:
The breakpoint command with the special flag is executed in advance before the application reaches the branching point. This preliminary action sets up the debugging state automatically, so that when a method invocation occurs, the breakpoint is already in place and ready to trigger, eliminating the need for subsequent manual breakpoint adjustments.
Solution Approach 2:
The breakpoint mechanism becomes dynamic rather than static. Instead of requiring fixed breakpoint locations to be predetermined, the system dynamically identifies method invocation points at runtime and automatically triggers breakpoints based on the set flag, adapting to the actual execution flow without manual reconfiguration.
Data Source
AI summary
Embodiments of the invention provide systems and methods for optimizing handling of breakpoints in a Java debugger agent. Embodiments provide a novel command that allows execution of the application in the debugger to stop or break at the beginning of a next called function or method (e.g., a “break on next called function” or “BNCF” command). When the BNCF command is given to the debugger, a flag may be set in the interpreter of the virtual machine to which the debugger is attached. On encountering a new method or function call, the flag is examined by the interpreter to determine whether it should stop or break in that call. If the flag is set, the interpreter will stop; otherwise the interpreter proceeds.