Java JSON data frame test example

A.java

// simple test case for generating a test data frame in Java in JSON and native form
// uses Java Jsonx API, e.g., compile with -cp javax.json-api-1.0.jar:javax.json-1.0.4.jar

import javax.json.*;

public class A {
    public static int n = 1000000;
    
    public static void main(String[] main) {
    	JsonObjectBuilder ob = Json.createObjectBuilder();
    	JsonArrayBuilder b = Json.createArrayBuilder();
    	for (int i = 0; i < n; i++) b.add(i/5.);
    	ob.add("V1", b);
    	b = Json.createArrayBuilder();
    	for (int i = 0; i < n; i++) b.add("X"+ (i % 10));
    	ob.add("V2", b);
    	JsonObject model = ob.build();
    	JsonWriter jsonWriter = Json.createWriter(System.out);
    	jsonWriter.writeObject(model);
    	jsonWriter.close();
    }

    public static Object[] direct() {
	    double d[] = new double[n];
    	for (int i = 0; i < n; i++) d[i] = i/5.;
	    String s[] = new String[n];
	    for (int i = 0; i < n; i++) s[i] = "X" + (i % 10);
	    return new Object[] { d, s };
    }
}