Error when saving composites id inside a for loop - spring

Question

I am trying to persist some objects that have a composite id. If I am only sending an array with one element it works fine, but it the array has more than one it throws an exception when saving the first one. public boolean
addParamsToChart(List<ChartParams> chartParams, Long chartId) {
List<ChartParams> chartParamsList = new ArrayList<>();
for(ChartParams chartParam: chartParams) {
ChartParamsId id = new ChartParamsId();
// id.setChartId(chartId);
id.setChartId(chartParam.getChart().getId());
id.setParamId(chartParam.getParam().getId());
id.setContextSourceId(chartParam.getContextSource().getId());
chartParam.setChartParamsId(id);
if(chartParamsRepository.save(chartParams) !=null) {
chartParamsList.add(chartParam);
}
}
if(chartParamsList.size()!=chartParams.size()) {
// something went wrong, delete previous inserted
deleteChartParams(chartParamsList);
chartRepository.delete(chartId);
return false;
}
return true;
}
[{
"chart": {
"id": 49,
"cv": {
"id": 1,
"name": "Money",
"category": {
"id": 1,
"name": "Euros"
},
"definition": "\"European curreny.\" [EU:euro]",
"enabled": true,
"cvid": "CC:1010"
},
"accountType": {
"id": 1,
"name": "saving"
},
"name": "Euro saving charts"
},
"param": {
"id": 8,
"name": "Totals",
"isFor": "Currency"
},
"contextSource": {
"id": 3,
"name": "euro",
"internal": "eu",
"abbreviatedName": "eu"
} }]
But for this having two objects inside instead of one is not working, throwing an exception at the first save.
[{
"chart": {
"id": 52,
"cv": {
"id": 55,
"name": "Stocks",
"category": {
"id": 1,
"name": "Stocks"
},
"definition": "\"General stocks.\" [GS:ST]",
"enabled": true,
"cvid": "ST:0111"
},
"accountType": {
"id": 1,
"name": "saving"
},
"name": "Stock saving chart"
},
"param": {
"id": 8,
"name": "Totals",
"isFor": "Currency"
},
"contextSource": {
"id": 6,
"name": "stock",
"internal": "st",
"abbreviatedName": "st"
} }, {
"chart": {
"id": 52,
"cv": {
"id": 55,
"name": "Stocks",
"category": {
"id": 1,
"name": "Stocks"
},
"definition": "\"General stocks.\" [GS:ST]",
"enabled": true,
"cvid": "ST:0111"
},
"accountType": {
"id": 1,
"name": "saving"
},
"name": "Stock saving chart"
},
"param": {
"id": 8,
"name": "Totals",
"isFor": "Currency"
},
"contextSource": {
"id": 7,
"name": "Sold stock",
"internal": "st_sold",
"abbreviatedSequence": "st_sold"
} }]
The exception I got is:
org.hibernate.id.IdentifierGenerationException: null id generated for:class eu.stocks.chart.chartParams.ChartParams