Clone Detection using Textual and Metric Analysis to figure out all Types of Clones

Abstract -A Clone Detection approach is to find out the reused fragment of code in any application to maintain .Various types of clones are being identified by clone detection techniques. Since clone detection was evolved, it provides better results and reduces the complexity. A different clone detection tool makes the detection process easier and efficiently produces the results. In many existing system, it mainly focuses on line by line detection or token based detection to find out the clone in the system. So it makes the system to take long time to process the entire system. If the fragment of code are not at exact code but the functionalities makes it similar to each other. Then existing system doesn't figure out the clone of that type of clones in it. This paper proposes combination of textual and metric analysis of a source code for the detection of all types of clone in a given set of fragment of java source code. Various semantics had been formulated and their values were used during the detection process. This metrics with textual analysis provides less complexity in finding the clones and gives accurate result

Detection of redundant clone relations based on clone subsumption

Clone detection has been presented in the literature at different levels of fragment granularity from functions, to syntactic blocks, to variable length strings of source code or tokens. String matching approaches, prefix and suffix trees, metrics, syntactic approaches and others can be used to compare fragments for similarity. Inclusion relations between source code lines may cause some clone relations to be redundant, when clones code fragments subsume each other. This may occur between nested blocks of source code, for example. An original method to analyze this kind of redundancy in clone relations is presented. The proposed method is based on efficiently combining clone subsumption information together with clone similarity relations on code fragments. The amount of redundancy in clone relations has been evaluated on two open source Java systems, Tomcat and Eclipse. Experimental results are presented. Execution time performance of redundancy analysis is measured and reported. Results are discussed together with further proposed research

Detection of Plagiarism in University Projects Using Metrics-based Spectral Similarity

An original method of spectral similarity analysis for plagiarism detection in university project is presented. The approach is based on a clone detection tool called CLAN that performs metrics based similarity analysis of source code fragments. Definitions and algorithms for spectral similarity analysis are presented and discussed. Experiments performed on university projects are presented. Experimental results include the distribution of similarity in C and C++ projects. Analysis of spectral similarity distribution identifies the most similar pairs of projects that can be considered as candidates for plagiarism

Assessing the effect of source code characteristics on changeability

Maintenance is the phase of the software lifecycle that comprises any modification after the delivery of an application. Modifications during this phase include correcting faults, improving internal attributes, as well as adapting the application to different environments. As application knowledge and architectural integrity degrade over time, so does the facility with which changes to the application are introduced. Thus, eliminating source code that presents characteristics that hamper maintenance becomes necessary if the application is to evolve. We group these characteristics under the term Source Code Issues. Even though there is support for detecting Source Code Issues, the extent of their harmfulness for maintenance remains unknown. One of the most studied Source Code Issue is cloning. Clones are duplicated code, usually created as programmers copy, paste, and customize existing source code. However, there is no agreement on the harmfulness of clones. This thesis proposes and follows a novel methodology to assess the effect of clones on the changeability of methods. Changeability is the ease with which a source code entity is modified. It is assessed through metrics calculated from the history of changes of the methods. The impact of clones on the changeability of methods is measured by comparing the metrics of methods that contain clones to those that do not. Source code characteristics are then tested to establish whether they are endemic of methods whose changeability decay increase when cloned. In addition to findings on the harmfulness of cloning, this thesis contributes a methodology that can be applied to assess the harmfulness of other Source Code Issues. The contributions of this thesis are twofold. First, the findings answer the question about the harmfulness of clones on changeability by showing that cloned methods are more likely to change, and that some cloned methods have significantly higher changeability decay when cloned. Furthermore, it offers a characterization of such harmful clones. Second, the methodology provides a guide to analyze the effect of Source Code Characteristics in changeability; and therefore, can be adapted for other Source Code Issues