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2. Critical Literature ReviewWe relate the methods with respect to the criteria. The visualise of the suggested approach is deputisement, wrapping and migration.2.1Replacements of bequest SystemsReplacement is not one of the policies. It whitethorn make sense to complete reshape of the bequest arrangement from scratch. Reshaping the application from scratch is bellly risky and time consuming, but has a trustworthy thing that it fulfills the organizations demands by giving a solution according to occupy and demand.Replacement can take place either by a system or incrementally. If the bequest system has defined structures then replace it incrementally. 2.2Wrapping StrategiesThe wrapping is another approach used for the implementation of SOA from legacy code. The utile legacy code is sticked with code wrapper to be integrated into an SOA system if the legacy system has a high business value and upright quality code, wrapping can be a good option. The toughened thing in this approach is that it does not change the fundamental features of the legacy applications that are being integrated. Wrapping will not solve problems already present, such as problems in maintenance and Upgrading. In many cases, canvas the internals of the legacy system is important and white-box modernization tools are required.2.3Overview of wrapping techniquesSneed 11, 12 proposed a tool supported method for maintaining legacy code within an SOA environment. Legacy code Segments that accomplish a desired service or information reform are identified using Clustering tools and a refreshful component is built by them. The new component is set a WSDL interface, and a SOAP framework is used. The technique has been demonstrated by wrapping a COBOL calendar function extracted from the legacy ... ...antage is that it is time consuming experient resources are necessary for this and source code is required. There is still no general migration technique that can be applied that solves al l of the problems that a developer may face. The required goal can be reachd by cartel two or more modernization strategies according to the advantages and disadvantages of every strategy in the context. The reuse of legacy system components and their exposition as go are not always easy. In certain situations their exposition, as operate will have an increased risk and a greater cost than their replacement solely with a new SOA architecture. The problem of modernization of legacy system has no perfect solution. Choosing a strategy is based completely on the objectives of the SOA architecture the budget and resources available and required time to achieve the project.