Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University

Repeatedly-Executed-Method Viewer for Efficient

Visualization of Execution Paths and States in Java

Graduate School of Information Science and TechnologyOsaka University, Japan

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Toshinori Matsumura, Takashi IshioYu Kashima, Katsuro Inoue

2Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University

Tool overview

REMViewer is a kind of Capture and Replay tool

Record an execution of a Java programVisualize multiple executions of a selected Java method

3Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University

Usual debuggerA usual debugger shows only a single point of execution at a time.

4Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University

REMViewerREMViewer shows each execution path of a method in a separated view.

Developers can compare executions and states of local variables.

5Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University

Usage

Executiontrace

program P Bytecode InstrumentationTool

program P’

REMViewer

Execute P’on a JVM

Select a method

6Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University

View

Line coverageExecution path

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View

State of local variables at the cursor

Cursor

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View

Select a line All the states of local variables at the selected line

9Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University

Example method (GCD)

Test casesgcd(3,3)gcd(6,-2)gcd(5,5)gcd(2,6)gcd(10,7)

public static int gcd(int a,int b){　　　　 if(a < 1 || b < 1){　　　　　　　　 return 0;　　　　 }

　　　　 int d = b;　　　　 int r = a % b;

　　　　 while(r > 0){　　　　　　　　 int n = d;　　　　　　　　 d = r;　　　　　　　　 r = n % d;　　　　 }　　　　 return d;}

10Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University

Tool demonstration

11Software Engineering Laboratory, Department of Computer Science, Graduate School of Information Science and Technology, Osaka University

ConclusionFeatures of the tool

Views for multiple executionsClassification of executionsStep next/back in a viewStep next/back in all views

ApplicationDebuggingUnderstanding existing test cases