procedure myProcedure (text, text) does not exist Hint: No procedure matches the given name and argument types

whenever trying calling any stored procedure in PostgreSQL 11.4 from my java application but getting this issue procedure pkg$my_procedure(text, text) does not exist. Note that I'm able to call the SP from DB.

im using PostgreSQL JDBC version 42.2.16

the SP declaration

create procedure pkg$my_procedure(i_param_name text, i_param_2 text, INOUT o_object refcursor)
    language plpgsql
as
$$

BEGIN
// myLogic

Java code to call the SP

        Connection con = null;
        CallableStatement callableStatement = null;
        ResultSet rs = null;
        Object obj = null;
        try {
            con = eRestaurantConnection.getConnetion();
            callableStatement = con.prepareCall("call pkg$my_procedure(cast(? as text),cast(? as text),?)");
            callableStatement.setString(1, string1);
            callableStatement.setString(2, string2);
            callableStatement.registerOutParameter(3, Types.REF_CURSOR);
            callableStatement.execute();
            rs = (ResultSet) callableStatement.getObject(3);
            obj = fillObjectInfo(rs);
        } catch (Exception ex) {
            LOG.error(ex.getLocalizedMessage(), ex);
        } finally {
            if (rs != null)
                rs.close();
            if(callableStatement!=null)callableStatement.close();
            if(con!=null)con.close();
        }
        return obj;

the Exception

ERROR: procedure pkg$my_procedure(text, text) does not exist
  Hint: No procedure matches the given name and argument types. You might need to add explicit type casts.
  Position: 6
org.postgresql.util.PSQLException: ERROR: procedure pkg$my_procedure(text, text) does not exist
  Hint: No procedure matches the given name and argument types. You might need to add explicit type casts.
  Position: 6
	at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2553)
	at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2285)
	at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:323)
	at org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:473)
	at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:393)
	at org.postgresql.jdbc.PgPreparedStatement.executeWithFlags(PgPreparedStatement.java:164)
	at org.postgresql.jdbc.PgCallableStatement.executeWithFlags(PgCallableStatement.java:83)
	at org.postgresql.jdbc.PgPreparedStatement.execute(PgPreparedStatement.java:153)
	at com.zaxxer.hikari.pool.ProxyPreparedStatement.execute(ProxyPreparedStatement.java:44)
	at com.zaxxer.hikari.pool.HikariProxyCallableStatement.execute(HikariProxyCallableStatement.java)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at net.ttddyy.dsproxy.proxy.StatementProxyLogic.performQueryExecutionListener(StatementProxyLogic.java:310)
	at net.ttddyy.dsproxy.proxy.StatementProxyLogic.access$700(StatementProxyLogic.java:36)
	at net.ttddyy.dsproxy.proxy.StatementProxyLogic$1.execute(StatementProxyLogic.java:122)
	at net.ttddyy.dsproxy.listener.MethodExecutionListenerUtils.invoke(MethodExecutionListenerUtils.java:41)
	at net.ttddyy.dsproxy.proxy.StatementProxyLogic.invoke(StatementProxyLogic.java:119)
	at net.ttddyy.dsproxy.proxy.jdk.CallableStatementInvocationHandler.invoke(CallableStatementInvocationHandler.java:36)
	...

the call from PostgreSQL

do $$
declare
	result refcursor = 'generated_result_cursor';
    rec record;
begin
	open result for call pkg$my_procedure(i_param_name  := 'name', i_param_2 := 'param', o_object := null);
    LOOP
        FETCH from result into rec;
        EXIT WHEN NOT FOUND;
        raise notice 're: %',rec;
        EXIT;
    END LOOP;
end
$$;

You created the stored procedure without doublequoting the name, so it is stored in lowercase.

The error message reports a functioname containing an uppercase. Since PG is case sensitive, the stored procedure is not found.

--> use a lower case function name

callableStatement = con.prepareCall("call myprocedure(cast(? as text),cast(? as text),?)");

all this point needs to be fixed in the above code. Thanks for @JGH that find the first issue.

1. you need to make sure that the case matches.
2. need to set the all param even if they are used for output. in case there is an output need to set them as null.
3. The last thing to do need to disable the auto-commit.

Java code to call the SP

        Connection con = null;
        con.setAutoCommit(false);
        CallableStatement callableStatement = null;
        ResultSet rs = null;
        Object obj = null;
        try {
            con = eRestaurantConnection.getConnetion();
            callableStatement = con.prepareCall("call pkg$my_procedure(cast(? as text),cast(? as text),?)");
            callableStatement.setString(1, string1);
            callableStatement.setString(2, string2);
            callableStatement.setNull(3,  Types.OTHER);
            callableStatement.registerOutParameter(3, Types.REF_CURSOR);
            callableStatement.execute();
            rs = (ResultSet) callableStatement.getObject(3);
            obj = fillObjectInfo(rs);
        } catch (Exception ex) {
            LOG.error(ex.getLocalizedMessage(), ex);
        } finally {
            if (rs != null)
                rs.close();
            if(callableStatement!=null)callableStatement.close();
            if(con!=null)con.close();
        }
        return obj;