Hi Kiran,
Below logic will help you to covert ABAP to JSON .
DATA: lr_writer TYPE REF TO cl_sxml_string_writer,
lrx_root TYPE REF TO cx_root,
ls_bapiret TYPE bapiret2.
TRY.
* ABAP to JSON
lr_writer = cl_sxml_string_writer=>create( type = if_sxml=>co_xt_json no_empty_elements = abap_true ).
CALL TRANSFORMATION id
SOURCE data = iv_data
RESULT XML lr_writer
OPTIONS initial_components = 'suppress'.
ev_json = cl_abap_codepage=>convert_from( lr_writer->get_output( ) ).
CATCH cx_root INTO lrx_root.
ls_bapiret-type = 'E'.
ls_bapiret-message = lrx_root->get_text( ).
APPEND ls_bapiret TO et_messages.
ENDTRY.
In the above logic iv_data would be your abap structure or table and ev_json would be response in json format.
please let me know if you have doubts.