SQLcl is the core scripting library for Oracle SQL Developer. That library has been factored out and wrappered with a command line to bring SQLcl.
The tool can be downloaded from Oracle.com here: http://www.oracle.com/technetwork/developer-tools/sqlcl/overview/index.html
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SQLcl is written in java and those java classes can also be leveraged directly. This can facilite running sql scripts from existing java programs. There are a lot of features that can be leveraged and this will be exapanding in the /java/ folder.
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